tig welding is fine for bench jobs, and as said is slower in comparison to mig. tig equipment is genrally more expensive too again the cheap equipment is shat compaired to middle of the the range stuff.

115 amps burning a 4mm rod you need 150 amps these no way on this planet that set will weld using 4mm rods in any position.

you need 2.5mm vodex E6013 all positional.

1.2 or 1.6 are usless rods as theres more flux/slag going into the weld then actaul metal. at least with a 2.5 u have a chance of putting down a decent weld. thats 90% of your problem mate