You can endo on a Safety of conventional geometry with normal rim brakes, that thing will start tipping at about half the rate of acceleration you can achieve on a normal bike. It might still be twice the rate achievable on an Ordinary, which is why we all ride Safeties now.
So like I said brakes that work, is slow you down, not insert your face into the road.
Weight might be back enough on that new thing to not endo.