Swivel seat using TI mast base

Has anyone considered or tried making a swivel seat which inserts into mast hole?

I was thinking a mast base, chunk of a similarity sized mast and the roller further part could make a nice spot for a swivel fishing seat for the second person to be able to ride facing the back.

I'd appreciate any comments about the strength of the mast assembly to handle a very short (not much leverage) swivel seat. I guess I'm wondering about the weight of an average size person on that area.

If course, I would not be planning to use the sail concurrently in this scenario.

Thanks in advance for any sage wisdom.

James