Which HP pin for what alloy and speed?

You may want to drop the tin and go to somewhere around an almost pure lead casting with the Hollow points…

I might potentially recommend looking at the attached test video on a heavy weight revolver HP Cast bullet & its expansion in ballistic gelatin … in the attached video… in this case an ~200 grain cast pistol bullet.

I tend to believe that what the attached video states near the beginning that the cast bullets are cast in almost a pure lead alloy, with the video detailing the ballistic gel tests which show the various HP expansion amounts, and the associated penetration depth of said HP… at various velocities…

The wheel weight design indicates a cast bullet of ~ 195 grains… with almost pure lead the cast weight I believe is mentioned to be almost ~ 200 grains…

Hopefully from that associated video you can potentially draw your own conclusions… as to what you need to do…

If not you can potentially PM me … for my separate experiences on that subject…

You might possibly want to watch the attached video to the end where you will see the steps of expansion and the associated penetration at various velocities…

NOTE … Too hard of an alloy will tend to produce a more brittle cast bullet that will not tend to expand no matter how fast you drive it… Your call on how hard you want the cast bullet to be …

https://youtu.be/0a8RVru54OA

Take Care, & Stay Safe…