for completion i will also explain how I managed to change the inner recoil spring, but by all means this process could be improved upon tremendously by someone with access to more tools than me.
first off: DO NOT ATTEMPT THIS WITHOUT A GOOD PAIR OF GOGGLES. this inner spring could really do some damage if it flew off in the right direction.
The tools I used were a 9mm ammo tray from an empty box of ammo, needle nose pliers, and a hammer. Getting the top of the assembly off wasnt too bad, but it took a lot more force for me than what I head it took in previous threads on this process.
Once the cap was off I cut out one square from the ammo tray, so there would just be one hole on the bottom. i put the new spring on the recoil assembly, then lowered the ammo tray piece over the guide rod. The tray I had (which I think was a tray of federal) had just the right size holes in the bottom such that the guide rod could pop through with some force, but the spring was too fat to fit through the hole (now that I think about it I may have hammered the guide rod through the hole first, took it out & put the spring on, then put the guide rod back through the hole). while i held the spring compressed with the ammo tray piece, I put it on a block and had a friend pop the cap back on with a tiny hammer. Now the spring is assembled correctly, but theres still a big piece of plastic on the whole thing, so I then cut off the plastic off piece by piece and viola, the inner spring is assembled.
for kicks I assembled the gun with a little bit of polymer still attached to the tip (cut flush so it was the same radius as the cap)and it did function-check properly. I thought about keeping it this way, and it would essentially be a little polymer "buffer" similar to what they sell for some full sized guns, but I decided not to because the polymer from the ammo tray cant be very high quality.
This description of events downplays just how frustrating the process was. To change this inner springs took me the better part of an hour.
If anyone has knowledge about an easier way to do this please tell me! I'm going to have to do it again in 6 months or so. I'm sure a part could be devised, but to my knowledge no such thing exists yet.