I'm with hang 9...
9, your right on, since you're asking a group of enthusiasts, of course we will, but your sloppy drunks in the lower end leagues will be your money.
The way I see it, I go to a pool hall for 6 reasons:
1. People
2. Atmosphere
3. Drink
4. Food
5. Tables
6. Competition
Neither of these is the smoking gun, cuz if you have a pool hall with ANY 5 of the 6 characteristics, your gonna crush it.
For example, you have a place where all the pool players hang out, nice dimly lit great atmosphere, with dark wood, comfortable...tables spaced out...u have a bar, not too far from the tables, beer, drinks, and friendly hot waitress, the place is known for great food, you have tournaments every weekend and leagues almost every week night...but the tables are tired valleys-they roll fast and straight, but a little tired. You're still gonna be packed wi people there to play on those shitty tables cuz u got the other 5 elements right.
Since people and competition will be scarce right when you open a pool hall...I would think that the extra investment of diamonds would pay off, to pull the people and the competition from competing establishments.
You don't want to open the doors missing 3 of the 6 components right off the bat. I would consider finding a way to get some local pros involved in the place too

give some incentives.