I use just egg yolks.
I use vinegar in mine because the acidity is more concentrated than lemon juice, yielding less watery mayo. I've never tried it but a stronger more concentrated vinegar might even be better.
If you want some mustard in the mayo, use very finely ground mustard powder instead of ballpark mustard.
Btw, you can repair a broken mayo easily by taking a small amount of storebought mayo, put it in a container and start working your broken mayo into it ( a little trick I learned from James Peterson book).
18.5" WSM and 22.5" OTG.