Hackers Help: MOLGER benches as bed frame?

Molger Plan

Photo: IKEA.com

I have just my first home and I need advice.

I am planning to use Molger benches as a bed frame and have sketched very roughly the plan using MS paint.

My questions are,

1) would the Molger benches be able to withstand the mattress + a combined weight of 200kg and

2) would it be advisable (or not) to use the single bed slats over the opening (will need to be trimmed down)?