VdW modifier for CHARMM LJPME simulations?

GROMACS version: GROMACS 2020
GROMACS modification: No

Hello,

I’ve been using a VdW modifier of force-switching for simulations using the CHARMM36 force field (C36). I’d like to run simulations with C36/LJ-PME, which was released this year. According to the user manual (Long Range Van der Waals interactions — GROMACS 2021.2 documentation), a VdW-modifier of Potential-Shift is recommended. In LJ-PME simulations, I assume I should no longer use a force-switching function because LJ interactions outside of the real-distance cutoff still should be considered.

How does a VdW-modifier affect LJPME simulations?
Should I use Potential-Shift for C36/LJ-PME simulations?
Will Potential-Shift and None give you identical results in LJ-PME simulations?
(Forces will be the same for both two options, therefore, chooisng either will be fine?)

Thanks!
Best,
Siyoung