Here is how I did it, nicked from the other thread about caster:
It gives 35mm more caster done like I have done it, compared to a ph1 wishbone.
However, you could actually add another 15mm to that if you accepted slightly losing some track, by elongating the inner hole backwards instead of outwards but I didnt want the extra caster enough to compromise a few mm of track width to get it.
This is how I did it:
Drilled a new outer hole, and elongated the existing inner one slightly, and trial fitted the balljoint both there and in the original place so I could take some measurements.
Then I plug welded the original outer hole (TBH you really dont need to im sure, there was quite a bit of meat between the holes but I can so I did)
Then I used a power file to make sure there were no highpoints that the balljoint might touch and not sit flat
Then I gave it a quick paint just to stop it rusting
Then while I was stood around feeling quite pleased with myself with how it had turned out (Im no fabricator TBH, just do bits and pieces) Mike from MWM who is staying with us this weekend proceeded to do just as neat a job (better if anything) of the other one in half the time, damn him and his expert welding skills, lol