NTB
Carb balancing is a yearly or less regular maintenance none event, so I wouldn't worry about it at all.
As for carb sockets splitting...true there have been some issues with them splitting but this is usually caused by the aircraft manufacturer not utilising the Rotax or similar airbox.These type of installations merely have an air filter hanging off a flexibly mounted carburettor, which is totally inadequate, hence in time the socket splits and the rumour starts that Rotax carbs sockets are a problem...
With the correct airbox utilised they do not split. My guess and I may be wrong is you are talking about an engine installation in a Bristell which comes with a Rotax copy ( their own)airbox which will do the job admirably and should cause you virtually no issues.
As for not fitting the Jab....wise decision IMHO regardless of what Farry says!