Big bad bag? Bag bad big?
Mix it about 1/3 perlite and 2/3 FFOF. One regular sized bag (what are they,6 quarts?) should do a big sack of FFOF at a lighter rate, but if your area is VERY humid, try adding EXTRA perlite, up to 50% overall! This is also a good trick in COLD areas or in winter, because plants use water more slowly and the perlite will keep your dirt from going sour on ya.

Put in as many CFLs as you can before your temps get too high, after your clones are FULLY rooted and taking off, of course.

A trick to making the transition from under the dome into the real world is to mist them lightly with wiltpruf or SMC leaf wash when you put them in pots, or even put them in pots and then back under the dome while you gradually harden them off- lift the dome for just a short time and put it back on as soon as you see the first hint of wilt.

Now go beat that dead horse! It doesn't care; it's dead.