I was also procrastinating and taking haitsuses so....

Depending on what your doing. Themes are easier. Restricted traits are harder. Coor swing is a nigtmare.

If you're looking at how much space you need, I tend to use one stable tab per project with 5 males and the rest females. I find that a manageable amount most of the time, and it's easy to keep track of. More space might be better, but any less would make the breeding difficult.

Also, make sure you have a naming convention for your pets. It's much easier to breed them when you can see which ones are part of the project and what/how many traits they have from the breeding menu.