I can change the height between the boards but need to drill holes on the side walls. You are correct and I also doubt the board can carry heavy equipment. Anyway it is a good reason to force me stick to my gears rather than looking for new one.
The preamp is Simaudio Moon PR 5.3 from Canada. The power amp is a class D design from Wyred4sound US. It produces very little heat even works for whole day which suit my closed cabinet design. I cannot think what will happen if I put a class A inside the cabinet.