For midges the best was the black absorbine ultra shield or Red Horse Super with Saltidin (alternative to DEET that midges hate)
Barrier is good for annoying, but non biting flies
I haven't found a really good one yet for horse flies, but was surprised the gits were still landing with the absorbine, but at least it was neurotoxic to them, but disappointing they got a mouthful of horse before death!
I've found the barrier super plus fly spray to be the most effective. However I've now brought a fly rug too as nothing seems to work against horseflies and also it costs alot to spray a 16.3hh horse twice a day xx