I picked up a 150 gallon that ended up being a leaker. I finally had some time this weekend, so I scraped off all the old silicone and resealed it. This is the largest tank I've done so far, but I actually thought it was easier because I had plenty of room to work inside the tank. I probably should've taken more pics, but here's a couple with it holding water (six hours since I filled it).
I wouldn't say the silicone looks professional grade, but it doesn't look horrible either. Next time, I might actually break down and buy one of those spatula type things they sell on tv to make the bead look better.