I highly recommend the LG-205 smooth plastic compact CT grips if you mean to use the pistol for CCW, either as a BUG or a primary sidearm.
If you ever need the pistol, it'll be in an emergency, and you WON'T have time to turn the master switch (as on the base of the larger rubbery LG-305 grips) "on".
The button on the front of the LG-205 grips which actuates the laser DOESN'T turn on accidentally, and I've carried my 340PD in a pocket holster this way now for a year.
Even with daily dry fire practice, which includes actuating the laser, I'm still on the first set of batteries.
If you use a normal firing grip, the laser WILL be actuated, so there's no realistic way to practice without it.
Once your pistol is sighted in (with co-witnessing of stock fixed sights and laser), there's no need to think about it further, just practice as usual. Should the laser ever fail, you use your sights as best you can. If the laser works, it provides several advantages, including target indexing from awkward and disadvantageous positions wherein sight use is difficult or impossible, and improved target indexing under poor lighting conditions.
Also, the smaller LG-205 grips are less likely to protrude from the pocket when the piece is carried in a pocket holster, yet they provide a quite-sufficient grip IME, even when firing .357 Magnum 125gr+P rounds, though I prefer and carry the new .38 Special Gold Dot 135gr+P JHP, which is loaded to hit to the same POI/POA as the traditional 158gr+P LSWCHP. The larger (longer) LG-305 grips are nice on a range-practice gun, but not the best choice for CCW, IMNSHO.
Best.