.38- I settled on 3.1 gr BE w/ a 158 gr cast SWC. I would start around 2.7 and see what works best.
.45- 4.6 gr of BE is my default w/ cast 230 gr bullets. IIRC, I started at around 4.2 during testing. 5.0 gr w/ a 230 FMJ was the go-to load for mil spec ammo for a few decades, so you could do worse.
Sounds like you could use more data.
“At the core of liberalism is the spoiled child – miserable, as all spoiled children are, unsatisfied, demanding, ill-disciplined, despotic and useless. Liberalism is a philosophy of sniveling brats.” — P.J. O’Rourke