Building stands for Harbeth 40.2's

I talked with my builder today. I told them I would reach out for more expert opinions on a final design.

Since the TonTragers are the benchmark for Harbeth stands, I'm trying to match them as much as possible.

Question 1- The TonTragers have a 1 inch riser in each corner of the top of the stand. Is this critical for optimal sound ? Or would it be sufficient for the speaker to sit flat on the top of the stand ?

Question 2- Obviously the top needs to be open except for the exterior frame, but can the base be a solid flat piece of wood...or should that be open also ?

Please chime in with any ideas...also I plan on using some good cone spikes on the bottom.

I've attached a pic of the TonTrager for reference for the above questions.

Thanks in advance.