Copper fungicide is good for peach leaf curl, which must be sprayed in the dormant season, before you see any green foliage starting to sprout. Beyond that, copper isn’t good for much on peaches, imo. Some peach growers use copper to combat bacterial spot, but it’s use runs the risk of phytotoxicity to the foliage.
For an insecticide. You might try the new version of Sevin.
It has the same active ingredient as Mustang Maxx, which is commonly used by commercial peach growers. The only difference is the concentration.
I would recommend this forum for learning to prune. Certainly there are books out there, but some of the more experienced folks on this forum have teased out the nuances of pruning various trees into different shapes.
In the Reference category of the forum, you can find lots of material on pruning fruit trees, as well as other aids to growing fruit trees.
Here is a topic in the Reference category, which may be of use to you.
You also may want to check out the Guides category.
Here is a topic in the guides category which may be helpful in pruning apple/pear trees.
Lastly, there are 3 youtube videos put out by NSCU for peach pruning.
Mike Parker shows how to prune new, young and mature peach trees. The videos do an excellent job showing how to prune peach trees.
Btw, depending on where you are located in OH, it’s probably not too late to be pruning peach trees. I’m in zone 6b and prune well into Oct., even November sometimes.
Here is a pic where I pruned a peach tree fairly aggressively in mid Oct. several years ago.
