200 hours chill difference is too much. Got find a tasty one that is around 400 this will give cushion.

Do you thin the fruit? You may need to thin more. I've not heard of chill hours affecting fruit size just flowering and late leafing out.

I just finished thinning my large peach tree last night. It took me over an hour as it had set so much fruit. I must have removed 70% as the ground was covered with little peaches. I like to thin mine at least 6" apart for decent finished size. Better yet 8" apart.

People freak out when thinning peaches but I have seldom found a crop of dinky peaches to be good. Nobody wants little peaches. Thin them hard! You will be rewarded with much better crop size.

@Melikeeatplants - Yes I do thin the fruits. I do at least 6" apart or more. Its just so frustrating getting large fruit the first year but after that the fruit have been small or like last year they were small and the rats ate all of them.

I go 12" on my trees. Still leaves loads of fruit and they size up well. Maybe peach was stunted from setting too much fruit early?

What's that spray called that fakes chill hours, dormex? Idk but if you really like the fruit it might be your only option short of building an ice wall around the tree.