The biggest limiting factor I have found in towing is that there is a point where the trailer will unload my front wheel and then my steering becomes more of a suggestion (about 100+ lbs… I am routinely exceeding the suggested limits)

I read somewhere that the safe cargo limit for a bike trailer is approx. half the weight of the rider + bike.

So, if you weigh 160lbs, and your bike is 30lbs, the max recommended weight of the trailer and cargo should not exceed 95lbs.

I've hauled over 115lbs with my bike (loaded panniers + trailer), but never exceed 65lbs in the trailer due to size/volume limits of the trailer itself.

But I do find that heavy weight causes the trailer to "push" the bike in ways that feel unsettling. 100+ lbs would make me uneasy! It's amazing that you're doing it! Kudos!