Bucker restoration resources

Hi to all Jungmann lovers.
Can any one explain the difference between a Jungmann 1000 and 2000 series fuselage. The weight restriction AUW IS 670KGS on 1000 series whereas it is AUW 720kgs on the 2000 series. Obviously this restricts the 1000 series on its load capacity.

The question is can this be rectified by structural modification or is it just down to obtaining and using a 2000 series fuselage.

I await any info anyone has on this issue.

Best Regards.

Bev Pook