6G 6" schedule 80 and mig downhill root. Kinda curious as to what you would set the gap and landing at and if you would weave from landing to landing or if the machine is setup correctly should it fill just buy keeping in the middle of the puddle.
e70s-6 wire, not sure of size yet.
if permitted, I would make th1 1/2" long tacks with tig only at 12 and 6 oclock and feather them with grinder or file.
gap set at 1/8" and land at 1/16" or less
I think 1/16" land helps once you get to the bottom overhead area.
you are right that if you have the machine set perfect, you can just drag staying in front of the puddle...thats the key to stay right in front but its hard to reposition your hands and body as you go to stay there in front of puddle without shootin thru.
I tend to use a slight wiggle because i think it slows down the speed just a bit and gives more time to reposition yourself.
you will probably want to make adjustments and weave more on the top and stay back further in the puddle and then when you get to the bottom, weave less and stay in front and try to keep gun angle the same, you dont want to push on the bottom for the root or it will be too flat or sucked back and you will be more likely to shoot whiskers if you have a push angle.
if you bevel angle is 37.5 deg, i think about 18 volts will be close.
wire speed depends on wire size but if you set 18 volts on scrap and play with wire until its smooth, you will be in ball park,