This is the same set i had trouble with on the vertical.

I have the vertical section and convergence completely restored, and it
displays a good picture.

The problem, is really poor focus.

This doesnt have your traditional electrostatic focus circuit, that has a
wire running to the back of the CRT with its own seperated pin.

It i believe, i may be wrong, but has electromagnetic focus. There is a
circuit somewhere that takes care of the focus.

I heard in the grapevine, bad solder around T502, and i also heard R8000
areas or something.

Anyway, I just went through the whole entire deflection board and redid all
solder. the focus improved a weeee bit. i also noticed, that if you look
closely to words you can see a slight 1% in and out of focus flicker. but
barely noticable. So i suspect there is bad solder somewhere

Where is the focus circuit and controls? where is R8000?

the deflection board has to be working fine.