I think people mostly use epoxy. I haven't done that myself since I've been mounting my connectors on a PCB. Another
mod I did used a press fit. Though I'm currently doing a box
mod that I plan to mount the connector to the chassis. I'm using the
510 connectors with the nuts, but they're overpriced. I'm hoping they will be available inexpensively from somebody sometime.
If you're talking specifically about the Mini-Mag Solotaire mod, I would imagine you could use a press fit with a shim (maybe even cut up an old atomizer), but if that's not do-able, probaby JB Weld or some other epoxy would have to do the job.