Ryujin
Legend
Yes, I'm sure you'll have plenty of resolution! As for the mounting question, go with whatever works for you. I will say that I discovered that it's important to make sure that my rig doesn't get in my players' way (or my way, but that's less of a concern). I'm not a photographer, but from looking at pictures of photography background stands online, it looks like that might get in people's way.
Keep in mind that you don't need the image to project straight down. I project at an angle (with the projector mounted on a stand next to my end of the table) and just adjust the projector's keystone to square everything up. It works great.
Some people worry about players' minis casting shadows, and it can be a little bit of an issue if a monster is "hiding" in a PC's shadow, but overall most players have found the shadows to be a cool effect and not at all distracting.
But in the end, go with whatever works for you!
Well I've got one of these:
Impact Background Support System - 12' Wide 3046 B&H Photo Video
It's 12 feet wide so it would be well back from where the players sit, while still being centered on the table. There's also an empty space on one side of the table, most days, so I could rig up a single stand like yours in that spot if necessary.