Fitting Multifix

[Dell]

A bit of advice please, I have made a new post for the Multifix size Aa on my Myford and as I didn’t use the steady pin initially I thought I would do it as I have it apart, underneath are three equally spaced holes although I only need one but am not sure how to get one in the correct place in the compound if it’s slightly out the holder won’t be square to the headstock , I know the Multifix will tour but it could be possible to get the hole half a hole out so if anyone has a suggestion or has already done it would be much appreciated , hope that makes sense.
Dell