Matt,
I haven't had my shifter apart but assuming it's the same or similar to my '94 LT1 car that I installed a short throw shifter into once upon a time, then there are some moving parts and possibly a bushing that are accessible from the top. You just have to remove the center console, a plate under that and the lower shift boot then you can see some things. The shifter cross pin you probably can't get out unless you're under the car.
Some videos from the old Hurst version:
https://www.youtube.com/watch?v=FvWDppPpBSo
https://www.youtube.com/watch?v=Zo6HXYIXSWI
https://www.youtube.com/watch?v=YKulzo1t9kY
https://www.youtube.com/watch?v=vEEsuBI-L8Y
Regarding fluid, I don't try to outsmart the OEM. Stick with AC Delco GM Synchromesh fluid. Engineers design and test to very specific fluid properties. So unless your box has been redesigned or modified and now requires a different spec fluid, just follow the FSM.