I would test a black and white pinto colt for LWO, unless I knew FOR SURE that he could not be a carrier. Now, don't get me wrong, that sounds like LWO+ is a bad thing, and to me it is anything BUT a bad thing. It means you have a frame overo and you would need to be careful who you breed to. If the colt is negative, you don't have to test any of the mares you might breed to him. If he is LWO+, just test the mares and don't breed him to any that are LWO+. And you have a 50% chance of getting a frame overo foal just by breeding him to a solid mare. Horses can have any combination of frame, tobiano, splash, and sabino patterns so you can also breed a LWO+ to any of these other patterns as long as they are LWO- (i.e. NOT frame). Our Rowdy bred stallion is a tobiano pinto, likely carries splash (has a snip and stripe), but is LWO- so we can safely breed him to anyone.
In order to be homozygous for tobiano (he can't be H/Z for frame overo or he would be dead from LWO)BOTH parents would have to be tobiano pintos. I never bother to test and would only do that if I were selling, as it would be a selling point. The first foal that isn't tobiano tells you he/she is not H/Z. But if you want to know, you can test for tobiano and the results will say if H/Z or not.
Now, a word about pintos - the don't always LOOK like pintos, which makes things a bit complicated. Friends of ours bred a tobiano looking stallion to a solid looking mare and got a lethal white foal. In that specific case both sire and dam were Rowdy bred. They were devastated.
Good luck!! So exciting to be where you are!!!