If you have a passion for the 38 LC, go for it. I really can't help you regarding your psi concerns and bullet weight. There is not much loading data for the 38LC out there - I even checked old Lyman data from the 1950s and 1960s and none was found.

When my 38 Spl cases split or get damaged, I toss them. But all the power to you to adapt your cases to 38 LC length.

Bet someone out there could answer your questions and concerns.