New to me .45 and a question

I just bought a used Pedersoli Tryon Creedmore in .45 Cal. The barrel is a 1 in 21" twist, obviously for conicals. My goal is a 200 yard deer/antelope rifle. I know that twist rate is to stabilize heavy conicals, but I don't need heavies to kill a deer or an antelope. I intend to go to the range this week to shoot some bullets I have in stock: 385gr Buffalo Billets and Great Plains. They are both hollow base bullets. I also ordered some NE 385gr conicals to try. I would prefer something flat based at around 250gr (Lee REAL maybe), but I not sure of accuracy with that twist rate unless I back the charges off, which is counter productive to my goal of flatter trajectory to 200 yards. I'm not going to shoot elk with it; I have other rifles (.50 and .54) to do that. I'm also in Idaho, so no sabots and pistol bullets. Is this doable or am I wasting my time/money?

Do you plan to Cast your own bullets, either now, or in the Future?

If you don’t Cast, or plan to, I HIGHLY advise you contact Bullshop, he is here on the Forum He makes a HIGH Quality Bullet, and Lubed with NASA, Which i feel is the Best Blackpowder Bullet Lube made. You can find Bullshop’s Contact in the Casting session here

I’m with Lewis on using someone like bullshop if you Don cast your own but I did have a bunch of 325 grain flat points I’d cast from 30to 1 alloy and they work really well sized 450 in a 45 I built.