I must stress that it is not only the angle from a side view (toe and heel) that needs to be in line with the horse, but the balance from side to side.
I know of a resort that takes excellent care of their horses, but.................... will hire the cheapest farriers they can find and I can tell you by looking at the shoeing jobs- would not allow them on my place. One foot longer than the other three, toes dubbed too hard or left too long, one side of the foot longer than the other, one front foot at a 52 degree angle, the other at about 48 and the two back something else again!!
If a farrier knows what he/she should about the big horses and being correct and in balance, then they should know how to do a Mini!!
And again, I say that it never hurts to certainly educate yourself, whether you do your own trimming or hire someone to do it, so you will know if your farrier is doing a correct job or not.
At a show in recent weeks, some folks brought in a Mini that they bought from someone I know- and knew the horse from the firsts owner. He is STUNNING now- all grown up, until I got to his feet!!! His heels are SO LONG that he is actually knuckling over in the front and can barely walk! In addition to the whole hoof being at least an inch longer than it should be all over. It was awful and they got the gate in the ring when the judge looked at the feet. Very sad as this poor little horse is going to have some serious issues if they do not find someone to get it right. They are doing it themselves (oh how hard can it be) and have just about ruined this horse. They received lots of advice on getting the horses feet back where they should be.