I have had a Rifa 88 for a long time. I actually bought the 3-lamp adapter when I bought the unit. So I can do the 1K light that comes standard, but what I tend to do more often than not, is to use some 1-into-2 converters so that I can plug in about 6-8 bulbs. I used to do this with CFLs (and you can mix and match the color temps to get what you want) but more recently, I've been using the Cree LED bulbs. They are about 90 CRI so not the best thing out there, but they do all I need. My diffusion has gotten a little brittle over time but not too bad. I'll probably end up replacing it with gridcloth.
One advantage of going with the 3-light adapter is that when I used CFLs or LEDs, the fixture stays cool. I can get it very close to the talent with no heat load, and I can break it down immediately with no ill effect.