Let's see....I scaped most of the 75 by myself. Once my wife got home she helped me rearrange a couple pieces. This was the most challenging one for me because I had a bastardized closed loop, and a freestanding overflow that I wanted to try to disguise a bit.
On the 40g cube octo tank, I had a bunch of large pieces that wouldn't really work in the 75, and I started piling them up. I'm not extremely happy with the scaping here, it's more difficult because it's viewable from 3 sides, and it's taller than it is wide/long. Thinking back on it now, I should have taken a hammer and chisel to some of the larger pieces, but a lot of it it was done after spending 3hrs on the 75g and I was pooped.
The 25g, was pretty much just a throw it in there kinda deal. This was done after the 75g, and the 40g. I'd had my hands up to my armpits in saltwater for about 4hrs at this point dealing with sharp heavy rocks, and just didn't give a darn anymore.
The 7g office nano was much easier, I had several small pieces, with some interesting shapes, and wanted to make some nice overhangs that the harlequin would feel secure in, but that would still be open enough that I could easily point him out to visitors.
I tend to like overhangs, caves, bridges, etc... Some folks like the wall-look where everything is on the back wall with a fairly steep slope, with lots of open space in the front. It just sort of depends on your taste. Smaller rocks give you more flexibility when it comes to stacking them. Having some mixed shapes also makes it easier to try a few different arrangements. In most of my tanks I've got some fiji, tonga branch, and eva plate. (I think that's the name of the last one...Kinda flat and plate-like.)
B