Re: Drawing from different types of holsters
Step 1 - Cut a hole in a box
Step 2 - Put your.......holsters in that box
In all seriousness though, it is entirely a personal preference. I'll tell you what I've found works for me, but it may not necessarily be what works for you. For concealed carry, I look at several aspects. The first and most important aspect to me is being able to draw the gun as quickly, effectively, and easily as possible. A gun is useless if you can't get to it, right? Next comes ability for retention (if you have to go hands on with someone). Last is comfort, although still important. If it's totally uncomfortable, you won't wear it, but honestly concealed carry is never going to be 100% comfortable. If it is 100% comfortable, you most likely are not carrying effectively or not using an effective carry gun.
For me, I have found all those aspects have led to carry at 3o'clock, OWB with a straight drop (no cant). 3o'clock IWB is fine too, but OWB can be considerably more comfortable. Depends on your attire. One thing I have found is that, for me, I absolutely despise cant in a holster. The typical carry position lots of people use is 4o'clock or almost 5o'clock with increasing degrees of cant, even as much as 45 degrees. I will tell you this is slow and can be extremely uncomfortable and inconsistent for the draw stroke, for me at least. Having to articulate your wrist in that manner, you also have less strength and will be less stable in the initial grip and draw. Straight drop is easy. Going down the list of importance, I will sacrifice some comfort and concealability for having an easier and more effective draw.
Appendix carry at ~12:30-2:30 is also another great method to meet the requirements of easy access, good retention, and a fast and efficient draw, though it is not for everyone. I like AIWB, however my gut doesn't agree with me.