I built a MLT using a 5 gal cooler that I already had using FlyGuy's instructions from here. The only difference is I used a Tee Fitting and created a loop with the stainless braid.
From the instructions it seems like people are saying that 12 lbs of grain is about the max for this design. Looking at Northern Brewer at their 5 gal all-grain setup they are using the same coolers but with a false bottom instead of the stainless braid. They claim that their cooler maxes out at 15 lbs of grain.
Looking through their kits as an idea of how much grain to expect for different styles, it appears that I can get by with my current setup if it maxes out at 15 lbs but if it maxes out at 12 I will have to upgrade to a 10 gal cooler.
BTW I'm starting out with batch sparging...
I know eventually I will end up with the 10 gal cooler conversion, but right now all I need to go all grain is a wort chiller. I can't afford to go all grain yet if I have to purchase BOTH the chiller and the cooler.
So, for those of you with 5 gal coolers, what is your max grain bill? Does the braid vs. false bottom make a difference in capacity?