Hi Steve,
there´s indeed a couple of interesting pieces.
And one doesn´t see them often; after all, it´s a rare breed and each is different. GP hardly made two identical pieces then and as a watch, the "bridges"-pieces are well on par with the finest that could be had then. Many regard that era as the one where the world´s finest watches came to life, so i think each is quite a benchmark piece.
The variants themselves make for an interesting variety; GP used a number of different bridge styles, with some even having "mixed" style bridges in the same movement. But all of them are Haute Gamme finish and top-performing chronometers, so "form and function" go hand in hand. That´s rare.
Naturally the number of swiss lever and spring detent escapement movements exceed the number of tourbillons a bit, but all in all finding one of these requires a lot of time.
But not just time - those non-tourbillon pocket watches are easily the same as a modern pre-owned wrist tourbillon. And one of the probably 60-70 historical tourbillons, particularly those in original cases, are quite significantly more than a wrist tourbillon (excluding the "Jackpot", maybe).
So yes, they made quite some interesting units then!
Which doesn´t say GP is a less interesting brand today; there´s at least one Three Bridges pieces with steel bridges for the wrist too (on custom order a couple of years ago)!
Cheers,
Peter