I have also recently weighed a new alu center beam at 1.5 kg.
The old one however was square box tube and was 4kg...
A large difference.

I will attempt to modify the tramp to allow the center beam to run under the tramp and exit through a hole near the rear seaction to allow the bolt rope to mount under the rear beam to deflect water.
Still I belive the debate on making the center beam optional will help older boats in cost and weight factors ways assuming it isn't a crucial part of the mozzie design.
It is about 100$ cheaper to have a 1 peice tramp made over a 2 peice design and there is less rope needed.