First post so be gentle. I went BIAB recently after starting with Kits, then extract, onto specialty grains then finally AG with BIAB. I'd always brewed big beers before AG and wanted to continue. Big IPA's, and Belgian Quads are my faves. So since starting BIAB, I have done a 1.091 Belgian Quad, then a 1.100 Belgian Quad, many 1.085+ IPA's, and most recently a 1.105 RIS. The smallest brew I've done is a 1.059 Blind Pig clone. My first BIAB ever was a Zombie Dust clone at 1.065 (which I fluked a BOS with in a local comp). So yeah, it can be done! To make it a bit trickier I generally do 25 - 28L batches, so I can get a 19L keg plus bottles from the batch
I use a 70L pot (18 or so gallons?), so fitting the grain in isn't a problem. Trickiest bit is lifting out the wet bag without a pulley, but I just lift a bit at a time then slide a wire fridge shelf under the bag to let it drain a bit before starting the squeeze. All good fun! Tomorrow is actually attempt 2 of Denny's Wry Smile, scaled to 28L, smallish one at 1.073 OG
First one was so damn good, I MUST do another! As for tips, I don't know if it helps, but I always do at least a 75 minute mash and am not concerned if it goes longer, then ramp up to 76 or so to make the bag drain easier. But I do the exact same process for the smaller beers as well. I actually have no changes to my process for any size beer, I just make sure I allow for a lower mash efficiency the bigger I go.