We are using a 15 gallon plastic right now and it soaks up water from the bottom quite efficiently. Didn't add extra holes either. We put about 2 gallons in the tray (1/2 gallon at a time) and a 1 - 1 1/2 through the top. But yes, it doesn't dry out as fast as the fabric pots as we can get 4 days or so rather than 2 or 3 days we did with the fabric.
Nis , how's all brotha! Ya , with the extra holes. The main reason i suggested that was cuz i've grown a lot in 5 gal pales and drilling those extra holes all around the bottom 3 inches or so really helps with O2 at the roots, they get air pruned and really grow well with added holes. But it's gotta be lots of em...1/4 inch. Of course it also helps with bottom watering too, but that's not why i started doing that...it was meant to add O2 is all. Works , you should try it ...Cheers eh