Upgraded cab insulation discussion

[PbFut]

Continuing with the fire damage, I ended up stripping the firewall engine side to metal with wire wheel and epoxy prime.
The interior side of firewall got so hot it charcoaled the jute insulation of the center section OEM pad and a bit of the inside cowl jute and a small part of the left pad in area of gas pedal. A question for those who have upgraded the insulation. Was it worth it? Does laying the rubberized material behind the gas tank add any benefit? Floor? The cab is gutted except tank. Now is the time to do the extra insulation if it is worth it. I need to watch my add-ons to this repair or a blown bank account could easily come about. Seems this stuff does add up so I am looking for input.
Thanks for help