wayback machine, yay!https://web.archive.org/web/20140211220115/http://techdocs.shimano.com/media/techdocs/content/cycle/SI/Nexus/InternalHub/SG-3C41/SI-35U0C-001_ENG_v1_m56577569830655189.pdf
But this makes no allowance for chain tugs etc. The important stuff is what bears against the dropouts, and how well it fits.
FWIW you will find that the locknuts are often not serrated on Nexus hubs, only the NTWs are serrated. If so you will need the NTW to bear directly against the dropout in most cases. Thus if you have a single-sided chain tug, it may be best to fit that (or the NTW) on the inside of the dropout, even if it is rather fiddly to do so.
If you have a double-sided chain tug (and there are special ones made specifically for Nexus hubs, in stainless steel) then you have no serrations that bear directly against the dropout. Any metal chain tug should help to keep the wheel in place without slippage, so that can offer a solution. If you use a nyloc nut on the chain tug, it'll stay put for longer.
Note that if your dropout is wider than the tab on the NTW then you are in trouble; the NTW may squirm and twist (in low gears especially) and this will let the wheel move around. Some shimano hubs only allow NTWs to be fitted on one side of the hub but even then If you can fit one NTW each side of the dropout this can help; there is just more grip there.
If you do that, you may find that the chain tug cannot be fitted easily, if at all. Sometimes you can put a kink in it so that it still works. If push comes to shove with a N3 hub I think it may be possible to
- fit a slimmer locknut (3/8" x 26tpi) on each side of the hub, to make more room on the axle for NTWs etc (you may need to grind the flats a bit longer on the axle)
- grind flats onto the end of the axle and use a NTW there even if it never had one before
- weld a chain tug fitting to a NTW, so that there are just fewer parts to deal with.