Hello, new here and first post. I have two front fenders I am working on. I replaced the lower fender cups on both, butt welded, planished each weld dot, then ground the welds down. I have applied 2 coats of SPI epoxy primer to the cups, let cure for 5 days, then I have sprayed 5 Star 2K high build urethane primer on top of the epoxy. I have metal finished the cups as close as I could to not have to use filler. One fender will be fine and will be able to block with the use of high build. The other fender will need filler or a couple more rounds of high build. My question is this, can I use the high build primer as the max that will be needed is an 1/8" or less, or should I limit the use of the high build primer, and opt for a filler over the high build? I will seal it once done with reduced SPI epoxy. I know I should have moved the metal a little more at this point, but am past the point of doing so. If a filler can be used over the urethane high build, what does anybody suggest? Thanks!