This question could have been answered with a single phone call at the Fodera shop (or an email to Phil) IMO. They really know what works best, what will help achieve the tone you have in your head.
I feel that a tone block has a pretty significant effect on the sound of an instrument (...when you break it down to the various wood components). More so that the wood used on the fingerboard (YMMV). Keep in mind that they call it a "Tone Block"... but no tone block might be the way to go for your Deluxe built.
No two (tone block) piece of alder/walnut/maple/chestnut/ash/... will sound exactly the same. The knuckle wrap test help them select the one piece that will correspond the most to your desired overall sonic signature of your built (fine tuning) in accordance with the wings, solid top, neck, fingerboard
et al.
I don't think I've ever seen a mahogany tone block. I'm betting they would advise against it if someone would ask.
If weight is an issue/concern, you might wanna entertain the idea to have the instrument chambered ($500 USD option).
You can also opt for a titanium bridge to lower the weight even more ($1750 USD option for a 5 strings).