Spook, sorry for the late reply as I've only just started using one - had nothing to report before!
I've just done my first 2 BIAB with a 33l Burco and everything went pretty well, I think. Managed to hit SG or above and get 23 or 22l into the FV.
Let me know if you have any questions etc and I'll let you know how I did it - wouldn't claim its the best way but it seems to have worked for me.
Cheers