Has anyone here ever tried low temperature epoxy primer? How was it?

I've got my body off the frame and am hoping to brush on some undercoating this winter.
There are a couple low temperature epoxies that pop up on google:
https://www.epoxy.com/899cold.aspx
https://protective.sherwin-williams.com/detail.jsp?A=sku-26767%3Aproduct-7006



The garage isn't heated, or substantially insulated and I'm not sure how effective heaters will be... maybe if i get several propane tank heaters?
Expecting daily lows in the teens/20s and highs in the 30s/40s for the next few months.

'59 Chevy Suburban, NAPCO