Yea, I've read several sources. I give 3 ff about 2-3x a week and once they're at about 1/2" leg span, I switch to pins.(you may already know this, just tossin' it out there anyways)
Fruit flies aren't any better for trues than tarantulas. I'm pretty sure the study that came to the conclusion that fruit flies aren't a good staple feeder for slings was actually conducted with wolf spiders.