A small detail but an important one. How much does one tighten the bolts at the base of a newly-installed toilet before the excess bolt materal is cut off? I'm afraid I'll overdo it and crack the ceramic. Should the bolts be hand tightened only?

I'm trying to get the bottom bolt off our old faucet in order to replace the current one that continually leaks. The bolt refuses to budge. It's highly corroded and spraying WD-40 on it doesn't help. I tried using channel lock pliers without any luck and I tried getting a 7/8 socket on there but it's just too small. I can't get an angle on this thing because of the 2 sinks and the way everything's placed. So, I have to have the pliers straight up. There isn't any room for me to get it horizontal which is why I can't get a good grip. Anyone have any thoughts on how to get this thing off?