More Abacus Madness

I've been tinkering with ideas for an abacus that hybridises the Montessori place value colours with the RightStart Math Al Abacus... I liked the idea that Joan Cotter uses the reverse side of her Al Abacus for trading exercises with twenty beads for each place value, enabling you to demonstrate trading occuring after the second addend. So here's my hybrid:

But now I'm not so sure that I like the idea of twenty beads per place... could it be confusing?

I shall have to play with it for a while.