Welding Tips and Tricks

tig weldng
2'' diameter ,St35.8 metal pipe
amp's 90
welding position 45°

procedure of welding (my welding)

2x joints one on 6h other on 12h
i weld by splitting pipe on 3 thirds on each side of pipe (to split heat)
so i start first left side 1/3 then i switch to right side 1/3
and to 2/3 till last 3/3
left side wasn't problem (don't know why root is smoth )
right side is problem , that last 4-5 mm on top joint
till that last 3/3 on right side root is fine
so to explain that ending on the right side

i weld till last 4-5 mm and then i switch to left side to heat that side to prevent cold joint
then back to right side and i continue and overlap left side by 3-4 mm
i don't see what i do in the last 4-5 mm so i panic a bit (because i know what will i see on end)

i add metal a bit over edge and if i go slow i get tits in root (weld boil)
or no weld in root (it's "hungry") if i go normal speed
from 10 root's 1 is kind ok (no x-ray on her so god knows is she ok )
to eye it's ok )
rest have "hunger" problem

how to weld that ending part ??
is there any video showing that ??
or can someone give really good detailed explanation how to weld that part

thanks !!

and sry for grammar, i'm from europe