Welding Tips and Tricks

Methods I have heard of but haven't perfected.
1/8 gap 1/8 70s6 wire walk over the wire at 70-100 amps.
1/8 gap 5/32 70s6 walk over wire at 120-150 amps
Back feeding while not looking through the gap 5/32 gap 1/8 70s6 at 70-100 amps.
Back feeding while looking through the gap 5/32 gap 1/8 70s6 at 70-100 Amps.

What method us the easiest to learn fast for an awesome root and what method is the most efficient?

I like a knife edge no gap. 3/32 wire @ 120amps.

If you use no gap how would you weld a joint that is not perfect or that you need to square up with a wedge. It seems like things might get bound up in a situation like that and may be metal bound?

That would be ideal fit up. That's what I try to achieve. Easy enough for test coupons, but yes a bit more of a challenge if you get stuck with a bad fit. Then I would just bump up filler wire size to accommodate only for the gap area. I carry filler up to 5/32 on my truck. If you get a one sided gap that you can't fill with 5/32 then I would suggest cutting back farther to get a good fit up. Or start cutting down fittings to make it right. I.E. If it was a 90 deg fitting and I had a real bad fit and no room to cut back then I would cut down 2 90's to get the correct length.