Strat neck needs more relief - truss rod specific questions

The neck of my strat has a a little too much relief in it, and I'd like to get it a bit flatter. I have the StewMac truss rod rescue kit and had previously added several spacers to help provide more of a bearing surface for the nut. But at this point the nut is as tight as it will go, and te neck still needs a bit more, so I'm thinking I should remove the spacers, remove a bit more wood (not much) to expose some additional threads, and use the extension nut that StewMac sells in order to move the neck a bit more. But before I do that, I need to get the last remaining spacer in the neck out, so I'm looking for any advice on the best way to get this out. I've included a pic here, and as you can see it's a tight space so this will be a bit tricky. Also, if anyone has further advice or thoughts on my plan to move this neck a bit more please feel free to comment as I would appreciate any guidance. Thanks

https://drive.google.com/file/d/1ql6...usp=drive_link