Hate to say this but you are doomed to fail from the start.
Why? There are PILES of tube type SW receivers available
now FAR cheaper than you could build one.

Hey, I get it. It'd be a fun project. I've thought about doing
something like this myself but seriously consider the cost.
Not just of the parts but the time involved in the design,
marketing, and *liability insurance*. Bet you didn't think
about that one!
Steve