What you're doing is OK, you'll need to reapply your combo spray after every rain. I'd recommend getting some Monterey Fungus Fighter which contains propicanazole (Orbit). Orbit is the most common fungicide cover spray used by commercial peach orchards, works better than captan to get clean fruit.

Also, get something for borers and apply to the trunk if you see any signs of them.

Hi:
My spray program for my 2-year old peach tree is similar to mc25a.
eskota - What do you recommend for borers, how and when.
Thanks.
Ben
Beach Park, IL Zone 5

about borers (Ohio State University)-

"Special Problems on Stone Fruit Peachtree Borers

The peachtree borer works beneath the bark at or near the ground level; it is primarily a pest of young peach trees but populations can build up and cause the decline and death of older trees. The lesser peachtree borer is a similar pest that attacks trees at wounds anywhere in the lower few feet of the trunk and scaffold limbs rather than at ground level. The presence of borers is indicated by masses of gum that contain small brown particles of bark at the base of the tree, or the occurrence of frass and empty pupal cases protruding from tree wounds. Adults (moths) of peachtree borer begin emerging in early June in southern Ohio, and late June in northern Ohio. Adults of lesser peachtree borer begin emerging about one month earlier than peachtree borer, and the lesser peachtree borer has a second generation in late summer.

Avoid mechanical injuries to the trunk and limbs, which attract borers. If evidence of borers is found, borers can be killed mechanically using a knife or flexible wire to puncture the larvae through the bark where fresh frass is found. It is important to prevent peachtree borer damage by protecting the base or trunk of the tree with an insecticide. New trees can be dipped in insecticide solution before planting. Insecticide solutions are effective when applied with a paint brush to the affected area on the trunk. The best time to apply a trunk treatment is at the time of peak emergence of adult peachtree borer, which is usually in early August."

I use Dursban (chlorpyrifos AKA Lorsban). You don't want to get it on the leaves or fruit. Most commercial peach orchards use this chemical, post-harvest. Other insecticides also work, generally mixed strong and enough applied to soak the ground around the trunk.

There are also pheromone lures for the adults, and nematodes that kill the larvae if you want to go that way. Some here recommend moth balls.