It is now not so much the quantity, but rather making sure you don't have them overlapping so that you would be seeing more then a few at a time.
HiTech
Need a little more guidance on what is allowed.
Typically there is a high thin layer that covers the entire terrain to give the sky some dimension with lower level cloud fronts scattered around. That makes two overlapping fronts so having absolutely no overlapping fronts seems a bit extreme on the one side and having 10 overlapping fronts looks to be a bit extreme on the other. The most I can see myself using is four: A high thin layer, a cumulonimbus tower with some stratus clouds at the base, and maybe something on top.
I would hate to design some nice effect only to find it crashes the server or ruins frame rate. Is there someway to tell if things are going badly?
Would like to see someday the clouds have a gradient from slight grey on the bottom to white on top and have a control to vary the overall shade from grey to white so we can create some nimbo-looking stuff.