For years I rode a hackney horse with cobbed tail
He was tormented int he summer by bugs and almost impossible to deal with.
One time we were at Martins Carriage Auction and I bid on an antique fly net and won the bid.
We would use this while driving (the only way we could drive safely in bug season) and then I tried riding with it. It worked for us! I put the saddle pad UNDER the flynet - then the saddle. Our original antique net had a breast strap and I made a tail cord to keep it in place.
We have since found the same type of nets (and use them for driving - I cant ride anymore) Check out this site - one of the best prices and great people to deal with
http://www.bigblackhorse.com/HorseTackFlyNets.shtml
The cord face masks also work well. What makes it all work is that the cords swing and move so bugs rarely land.
I would be cautions about using it if I were going through dense brush/bushes etc
I use the draft size on my size 84 blanket DraftXPerch
most horses should do OK with the horse size and the used to make a pony/cob size that friends have used on a 14H morgan. I should be fairly easy to downsize as its nylon and could be cut and heat sealed the new edges. (It is made to attach to a harness neck strap in front, but you can ignore that)
My concern about the bug armor is IF any of those vicious greenheads or deer flies got under the net, they couldnt get out
We DO have a friend with an driving and endurance arab who uses the Cashel armor both riding and driving and she likes it. My old horse was very leary of approaching her horse the first time he saw the full get-up, but he got used to her once he realized that they WERE a horse.
My hores ( 5 have used it now) have had no problem getting used to wearing the string net
the face masks they show also work well - we used them riding for years before Cashel came out with their facemask
Also love the crochet earnet you can get at most tack stores
and one more thing - we always used to ride with a flywisk. (crop like stick with horsehair tail attached) those things are great because YOU can flick off the flies where your horse cant reach