I was going back through some old posts and found a short discussion of hole diameter in trumpet mouthpieces. One member noted that they, "prefer 5/64" and 3/32" hole size in [their] mouth pieces...[and] sometimes bore the mouth pieces 7/64" to get more of a jake or gobbler yelp sound." I was curious to hear what others think about hole diameter. What widths are you using on your calls?
The "internals" (MP hole included) are a system, can't say one size is preferred, as it all depends on everything else built into the call. I have used the sizes you mentioned, as well as others, they will all work if you figure out the exact combinations. And hole size does not in itself determine the pitch of the call, it will affect it, but other factors may push it one way or another as well. Trumpets look like a simple call, but they are actually complex little rascals to build, with a zillion potential twists and turns along the way.
Spur Hill trumpets gives you a choice of 3/32, 5/64 or a #45 which is a size in-between the other 2
most people seem to prefer the Buice #3 or #4 mouthpiece
those should get you started
It's not just internal bores but the lengths of each component also. Takes a lot of experimenting on your own to come up with what YOU like.