The harness as pictured is looking quite nice-very comparable to, say, Smuckers!
The browband looks a bit odd to me; looks as if the blinder support is pushing it outward?? I definitely like the chain on the browband-have had several with it; it is SO much handsomer than dots, IMO! I do like a breast collar with at least a bit of a windpipe V; however, it IS a challenge, I believe, to configure it just right for a mini. I have a Smuckers Pleasure harness that has a simple, unpadded but reasonably wide, breast collar with an excellent configuration of the V-fine for everyday/show ring driving. I recently got a padded, deep V breast collar from the Carriage House for my B mare, and I LOVE it! The smaller the mini, though, the harder I think it would be to build such a breast collar to truly and well fit the horse. I would agree with Leia's idea of larger, and perhaps, slightly higher-placed, terret rings on the neckstrap, also.
As for the noseband/separate cavesson-I did have a very knowledgeable, national level, longtime mini trainer tell me that she'd had better luck with a horse that wanted to fuss with the bit(as one of mine was doing, even in the basic Myler), by using a separate cavesson. Sure enough, it did make a difference with THAT horse! However, for the most part, I have seen little to no difference in effect between one or the other. I,too, start my horses in an open bridle and NO noseband-have never had one I thought "needed" a noseband; when one is in use, it is adjusted so that one-two fingers(depending on whose fingers they are!!
)can be slipped between the buckled noseband/cavesson and the horse's muzzle. I do think that the idea about a self noseband helping keep the cheekpieces of the bridle, and therefore, the blinders, from gapping away from the sides of the horse's head, might be most applicable to a (usually!)cheaper,lightweight, 'flabby' leather--OR, to a poorly fitted or unsuitable-to-that-horse bit--and is seldom much of an issue when everything fits well and comfortably--JMHO. I have to say-I have never had a problem with a separate cavesson having the cheekpieces/headstall slide forward?? A bit of 'shaping' helps, with the actual noseband being slightly wider where it centers on the front of the face. Perhaps a snugger fit, where it "slides" through the headstall?
My "everyday" harness-the first I ever bought, in '85, and still in quite regular use, is a Smuckers Lite, in russet(natural, undyed)leather--it has a self noseband, and a treeless harness saddle(I use a fleece harness pad), lightweight, straight breastcollar with only a single neckstrap--not what I want for serious, long distance or marathon-type driving, nowadays, but quite suitable for training/general daily use, because it is well-made and well-fitting. Being able to 'switch out' a deeper V'd and padded, buckle-in trace, breastcollar with a more basic V'd one sounds like a good idea, too. Also, I'd definitely be in favor of a wider, more well-padded harness saddle, with good wither clearance in the gullet. Like MiniHGal, I've NEVER seen a sliding tug holder on mini harness. Though it has its place, I don't see it as hugely important on most mini horse harness. Yes, it's most suitable with gigs/gig shafts-and there simple aren't many of those for minis. I, too, have read that they aren't suitable for some marathon vehicle setups? I believe they are only really suitable for a two wheeled vehicle, also-so wouldn't be desired with a 4 wheeler.
The tugs pictured are a basic open tug with a holddown strap, attached to the lower outside of the tug loop, which then buckles into an overgirth strap that is attached(usually, not permanently, and in a 'sliding' manner, as with wrap straps)to the girth itself. Tug stops(and, I believe, breeching) would definitely be needed with this type of tug loops; without breeching, you would really have NO 'brakes', except the tug stops--and they wouldn't really be much, though you might "get by" in the flat show ring(see more of post, below!)
Though it isn't pictured,I presume that this harness is to be offered with a breeching? I would surely suggest that being an option. Though most may want it as a show-only harness, it would be much more versatile in application if it could be ordered with a breeching-which can easily be removed for the breed show ring, but used for "real world", and/or ADS/ADS-type showing. Dr. Pam mentioned the placement of the breeching carrier straps as being crucial, and this is VERY true-another 'tricky' situation where proper proportion is VERY important!
One other thing-about Tilbury(French)tugs, which pull down snugly onto the shaft-like you might put the end of your belt back through the buckle and pull it tight, like a noose)-when I bought my first real 'show' harness(a Lutke), I was "instructed" to get Tilbury tugs, and I did; however, I never really LIKED the way they worked, but didn't know why. I recently learned that they are actually considered correct for a single pulling a FOUR wheeled vehicle--and when you think about it, it makes sense. If I were ordering show ring harness(for a single mini,to pull a cart)today, I would not order Tilbury or French tugs, but instead, either open tugs with holddown straps, or open tugs, with wrapstraps--AND breeching! If not using breeching, one could probably 'get by with' wrapstraps 'only',for a two wheeler, in the flat show ring, but tug stops would be a requisite, with breeching, if using the open tug loops and holddowns-and desirable with either configuration.(I don't believe it is really safe to use open tug loops with holddown straps without using breeching-one reason why people opt for Tilbury/French tugs, even though they really aren't proper for a single pulling a two wheeler. I think the conception may be that the Tilburys "look fancier" than wrap straps, and they are used , albeit improperly, for that reason.)
All in all, the harness looks like an excellent 'work in progress'--good job, Dr. Pam and Lisa of Ozark!!