I will continue to buy your custom products in preference to anything off the shelf. If I need a holster right now there is usually something regrettable out there on the market, but I'd still replace it down the road even if it was a pretty good piece of vacuum formed leather.
So, having established that I'm not a potential customer for the line, I would ask you what my PLMs have always asked me when I wanted a new line: what void will it fill?
Current off the shelf leather holsters from Galco and DeSantis are crap and are usually blatant copies of talented workers' efforts. I am apparently the only person on earth who is bothered by that, so it's just a question of crappy.
I'm quite sure you would make a better holster than Galco. Who will perceive that?
You plan to capture, I think, demand that is currently coming to your attention through your site, that is escaping due to lead time. That makes sense to me. I am not sure how much of your core business you will cannibalize, but I hunch it's not a ton.
How many people are going to be like the poster above who says "I want it just like that but customized for my WML... wait, that's 16 weeks? Well, I'd prefer that it be horsehide rather than cowhide... wait, that's just the stuff that you already sell for slightly higher and a lot longer?"
I'm not trying to discourage you, but try to picture your potential customer and think about getting him all the way through the sales process.
As far as model / fit, I understand the guys who are saying Glock, and depending on your potential customer that might make sense. I would say there are a lot of 1911s in the world and not a lot of good off the shelf holsters, certainly fewer than Glock. More extremely, you could choose to be the only guy who has an off the shelf P320 holster; I honestly think that's going to be a very active market and you would have a chance to beat the rush a little. Just a weird thought. There are probably too many P320s in the world.
Rake would depend on gun. A big ass gun like the G17 or GM would be 20-25. Commander / G19 15, wee guns 10 or less.