Vintage Losi/Associated ballstud sizes

[Miggers]

Numero uno son rolled up t'other day and drops half a dozen turnbuckles
fitted with RPM long(26mm end to end)ballcups into my sticky mitts.

Tried them on my modded Cobra(it's fitted with a complete B3 front end)and they won't go anywhere near the 4.8mm ballstuds it's fitted with.

Giving the cup ends a measure with my vernier calipers,the open end comes out at a touch over 4.15mm,so would 4.3mm ballstuds fit(1.5mm seems a lot to ask some how)?

The guy who gave them reckoned they were off a Losi XX,so in that case,what size(guessing Imperial really)were XX/B2/B3 ballstuds?

Ta.