About fun and howdah pistols.

I'm as big a lunatic fan of the howdah pistol as anyone.
I have completely disassembled a period original 577 Howdah and drawn and dimensioned diagrams of every part and assembly. Some day I'll make a reproduction.

Also I'm as big a sucker for a hotrod handgun project as anyone. I really like cool handguns and I really like offbeat wildcat cartridge projects.
I think you should make up as many cool handguns and handgun cartridges as you can afford.

On the 500 and recoil or shootability - they might not be as bad as you think.
All the big bore cartridges can be loaded down.
When they can fit in a Ruger, they can be really handy.

This is a custom Alaskan in 500
I've shot it with full house loads, one handed, and I'm not a big tough guy.
With lighter loads it's a peach, and it packs really nicely - and it's accurate.

Don't hesitate on making your project ideas come to life.
You won't miss the money once it's been spent on the project, and you'll have the gun of your dreams, however it's loaded or whatever you name it.

Here's a company who will make brass for you, with your own cartridge name and caliber on the headstamp.

https://www.rccbrass.com/