Has anyone used wall mounted electric panel heaters as a supplement to their shop heat?

My shop generally stays between 40-45 F when not heated (attached 2 car garage, well insulated, ~ 400 sq ft) on most winter days. When temps dip into the single digits the shop temp will drop to ~35 F.
My main sources of heat are an electric 1500w ceramic heater and 18000 btu propane heater. I can raise the shop temp from 45 F to 60 F in a little over an hour.

I am not expecting to heat the shop exclusively with the panel heater(s), just keep the temp moderated slightly.
I considered oil filled radiant heaters, but I don’t like the idea of taking up floor space and moving them around.

Has anyone tried something like the Envi heater from Eheat?
There are other brands as well. Basically 400-500w units that rely on natural convection heating air drawn up from the floor.