I was able to learn from everyone's replies and apply it to the deck lid. (Thank you)
I ended up needing only a bit more metal glaze to get everything feeling smooth... I even worked out a small wave on the other half, which I 'thought' was complete.
I got it to where I was comfortable enough to spray 3 coats of SPI's 2k. I have started blocking it and finding that I am pretty straight. I did have some spray imperfections, which you can see in the picture where I re-sprayed... they have since blocked out smooth.
So, I was under the notion that the SPI 2k primer was not a high build like featherfill? Was I, this entire time, questioning the use of a sprayable body filler while it being a part of my spray plan all along??
Is the SPI 2k just the same as using featherfill?