I can't speak for the Graduale Simplex, but broadly speaking, the Triplex replicates the spacing of the Vatican Edition, as did all the previous Solesmes publications, such as the Liber Usualis, since the Vatican Edition was propagated. There may be a few inadvertent discrepancies here and there, but it is certainly possible to sing in Pothier's accentualist manner from that book.

My understanding of all the post-conciliar editions is that the Vatican Edition retains its status as the official text, so I assume that all of these various books try to replicate the spacing.

I find Pothier's theories extremely interesting (he is a fantastic writer and his book retains so much value after almost a century and a half) and not easily reduced to simple principles, so it may be indeed difficult to do what you are suggesting, just given the overlay of so much contradictory rhythmic information on the page, but I would be interested to hear how you fare with it.

Jeff's talk is a good start, and Jeff has done a lot to promote Pothier. But he still often defines it in opposition to Solesmes, so he makes it sound more equalist than I think it probably really was.

If you read French, Pothier's book is invaluable. I also compiled some material on this at the colloquium a couple of years ago and I will attach that here. I cover Pothier's views in the first chapter. This is my attempt to lay out four different methods in as irenic a manner as possible. I do really love Pothier and consider him very inspiring. I hope you find it useful.

Someday this might be a book, God willing!