Hi shift_47_
All things being equal, I’d select the more modular approach. My reason would be because should you need to do any changes for comfort reasons that it’s easier to change an individual 3" layer. Assuming the mattress zip cover is appropriately sized, the pieces won’t really move around.
I’d you are really concerned about the top layer, you could probably ask the mattress maker for the single piece comfort layer of option 1 with the 2x 3" support layers of option 2.
I’m assuming, in addition to being pressure mapped you’ve evaluated the mattress for PPP yourself using Phoenix’s wonderful tutorial.
https://forum.mattressunderground.com/t/how-to-look-for-and-find-the-best-mattress-for-you-read-first
A 30/40/30 comfort layer is a bit firmer…it could absolutely be suitable for you, so if it feels good and accomplishes PPP then all is good. PPP gives you a second means in addition to pressure mapping to evaluate the mattress suitability.
Good luck 