New member with questions about firewall

[hhylton]

Hello, I'm a new member and I need some opinions on cleaning up and smoothing out my firewall. I have a 70 c10 that I have been working on about 8 yrs off and on (off more than on). I am welding up the heater core and vent opening and trying to smooth out the areas of spot welds which are mostly on the driver's side. I have welded in a section of the heater core. I have filled in most of the holes but have some spots that I haven't completely filled in. First question is should I continue to fill in all of the spots by welds or fill in the remain spots with filler? (see pictures) Second question, does anyone recommend filling in those spot welds with filler and etc or is it a big hassle to even attempt it? I would appreciate any advance and or recommendations.