Alright fam, after weeks of messing around I can confirm that the Daiwa GS25HS, GS20HS, and GS-15AC (to an extent) JDM baitcasters share nearly identical parts ane build as the PT33SH (and other reels in that family). I was able to use the super ceramic #7 tune bearing upgrade kit for the PT to upgrade the internals of the GS series. They are marked as 2 bearing reels, but the bearings from the kit were direct fit for the plastic and metal bushings located in the same spots as the bearings would be in the PT33SH schematic.
However, the drive ratio is different between the reels so the drive gears are different sizes, facilitating different carbontex washer sizes. But, the shaft and most of the rest of the drive gear stack are all interchangeable which is also nice.
I found this to be pretty cool, because now you can upgrade these relatively cheap GS reels to 5 bearings making them a lot nicer to cast if you're doing something besides jigging on them.
It also opens up the list of donor reels for parts substantially, as these reels can be easily found for $10 plus shipping to keep your higher speed retrieve PT series in the fight, or vice versa.
Happy Fishing!