For the 6x7 models: I've never checked on the exact opening of the 6x6 carriers vs the exact image size on my 6x6 negatives. I don't know of any oversized 6x6 carrier for the LPL, but the glass 6x7 negative carrier would give the option of opening the built in masks to a slightly wider opening for the horizontal dimension--no modification needed to do that. If any vertical opening additional width is needed, you can remove the masking blades and trim them a little--easier than working on the opening on the carrier.
If you have one of the 4x5 models, then the glass carrier can open to 6x6 or slightly larger without modification--just add the rather expensive masking frame to the enlarger..