Please help - I'm at my wits end...

My little one is nearly 7 months old and we are averaging 2-3 blowouts a day.  She is breastfed and we've started BLW but she isn't swallowing enough yet to solidify her poop.

She will have a blowout up her back everytime she poops while lying down (which is usually twice a night).   She will often have a blowout out the leg openings during long car rides or stroller trips.

We are currently using pampers (swaddlers and overnight) but have also tried huggies, luvs, and honest co.  She is 17lbs and we just sized up to size 3 and continue to have the same problem.  We've tried tighter, looser, and everything in between to no avail.

I'd prefer a diapering solution rather than diet change as we are strong supporters of BF and BLW, but at this point I'll take any recommendations.  

And any suggestions for a good stain stick? Pretreating with liquid detergent isn't cutting it anymore.

Thank you in advance for your help/recommendations.