What I do to make sure a tank can handle the appropriate bioload, is to add some pure ammonia to the tank every day. For instance I have a 60g hex that is cycling ATM and coming along nicely, but before I put anything in it I have been putting a small splash of ammonia in (maybe 5ml worth) every 2 or 3 days, after the levels reach 0 0 again. When you can add a fairly large amount and see it hit 0 0 the next day, then you can be completely confident that you can handle a bioload much greater than you will put in it.
I did a fishless cycle on my 120g freshwater this way adding 5mL of ammonia until I got readings of 0 0, and I added approximately 35 fish the first day and have never had the levels go above 0 0 still to this day. Very cool (whereas putting fish through ammonia is very uncool)
The ammonia must have no surfactants. If you shake the bottle it should not foam whatsoever. I got some from walmart if that helps, i could check exact ingredient list and brand when I get home if that helps you.