On my 55 I used 2 x 1-gallon OJ jugs with 1/2 tsp yeast and 6 cups sugar and filled them up until there was only about 1" of space. I ran both into a "filter jug" to catch DIY gunk/snot and had only 1 final tube going into my powerhead for diffusion. I was getting about 4 bps for up to 2 weeks and I changed out my mixtures every 2 weeks.
The only problem using the Hang on Back filters for CO2 dispesement is the water surface agitation they provide. A good deal of your CO2 will be gassed out before it even makes it into your water column. HOWEVER, that could also be your safety net if your DIY starts producing several B'sPS...it will prevent CO2 overdosing.
Good luck finding your perfect mix, and don't be afraid to play around with different ratios.
-Dave