New Build Questions - Heater and Aluminum panel coating

[whinz]

Hi everyone. I just got my new build started. Finally unboxed everything. I identified a few dozen missing parts and over 40 on back order. But I am optimistic. :-) Although I have been doing research for years, I thought I would ask a few questions, before making any key decisions.

1) Are there any small, compact and easy to install heaters anyone would recommend? FYI. I do plan on buying the ff metal firewall forward kit to help with space.

2) I just read a build thread where someone sprayed truck bedliner on their aluminum panels. I was impressed. It looked excellent. Anyone have experience or thoughts on this?

Thanks in advance Walter