I would try to get the pinholes corrected with the weld. Either you do not have enough gas, or you are not using flux core wire, or you have other contaminants causing pin holes

for some minor blemishes, I have used lead in the past as well as filler over POR15. I would not recommend the lead to a novice.

POR15 is a good product, not as good as all the hype, however better than most I have tried. It does need to be top coated.

The problems we face today can not be addressed at the same level of intelligence we were at when we created them - Albert Einstein Or with the same level of $ - Me