Just to add to what Nick says, my method is a bit cumbersome and time consuming, especially the sparge step, because you are sparging twice over. It may not suit you.
Having said that, it isn't hard to hit 70%, just squeezing and not sparging.
Given I paid $12 each for my pots, I'm satisfied on a cost/time basis to do a full size in them. I can get 5.5kg split between the two quite comfortably. I bought an esky for a mash tun, but my dodgy DIY skills meant that after 3 batches, I went back to the 2 pot method and have stayed with it.
What I was saying about your 10L pot and colander, and I think this add to what Nick says (about no sparge method) - if you don't have the ability to hoist or strength to hold up 3.5kg + water, then the spare pot and a colander will be great, because you can whack the bag in there, have two (gloved) hands free for a good squeeze and then start the boil. Naturally, some liquor will continue to drain from the bag, through the colander and into the pot, and these runnings can be added back into the boil.
It requires less equipment (if you don't already have it - I don't) and his a good spot where you use the method Nick describes above, whilst not having to hoist, hold or anything to do the squeezing.
Like what was said on another thread - we all have different methods that suit us for different reasons. Find something that works for you from the mountains of (mostly good) advice you will get, and run with that. I think the interesting this is, that there are so many different methods which are all the cross bred american hop versions of BIAB and the stovetop method.
Good luck.
Goomba
