I use 52/17 right now, its not especially easy to skid, but it works and you go fast. should be fine.

I run 46/18 which has turned out pretty nice for the hills around here. I too had one of those permanent 52t chainrings attached to my cranks. I mounted my 46t to the inside position and ground the teeth off of the 52t to make a sort of urban bashguard. I actually like how it looks and am in no hurry to buy new cranks.

52/12.

Massive quads will ensue.

That's 80 gear inches, more like track gearing. Might want to dial it back a little.

I run 50/16. ~83 gear inches. I'd suggest something a little lighter.

haha 52/12 is insane, I don't think I'll go with that but I like the idea of attaching the smaller chainring to the inside of the bigger one and grinding it down. Sounds like the 52/20 ratio is gonna be a little rough for around where I live (it's hilly), so I think I'll use the smaller one and cook up something like a 42/16