I've reloaded thousands of 9mm Luger using various FMJ and LRN profiles. It's been my experience LRN has to be loaded shorter, depending on bullet ogive profile and chamber leade.
For example, I can use a 124gr FMJ AT 1.10, but the same weight in LRN has to be at 1.07 before it passes the plunk test. My loads cannot approach max charge due to this so I back it off a bit.
I know nothing about 9mm Largo except for what I've read. It appears there is a bunch of extra space available using approximately the same powder charge as Luger. I would ass-u-me you could load Largo fairly short and still have considerable space left to not worry about overpressure.
Again, just an assumption.
BTW, you want at least .001 over bore diameter with lead bullets, preferably .002.