What shocks and specifically what version is on your Spyder currently? If your setup has either hard coated or Kashima bodies, that is a respectable upgrade from non coated bodies.
You mention that you are working with a suspension tuner, he should have an Intercomp or similar spring tester. Have the oem spring tested then decide if upgrade springs are needed.
If you setup has Kashima coated bodies, you are close already, work with your suspension tuner and have him respring if needed and then revalve the shim stacks. I have said it before, I am no Fox fan boy, but they certainly build a very good product to work with. There are only a few top tier suspension companies, typically Kayaba, Showa, Ohlins, WP, and Fox. The smaller companies such as Wilburs, Elka, Penske, Race Tech, M2 and others can build good stuff, but not always. Being smaller they do have an ability to try and focus on a specific model others may not. Case in point was when I wanted Ohlins on the Spyder. Apparently Ohlins in Sweden has no interest in Spyders or did not at the time.
If your suspension shop is a full line Ohlins dealer, it is possible they could mix and match bodies and shafts to build Ohlins. This is what Ohlins NA suggested. Assuming your shop has a shock dyno, they can easily mimic, then optimize the shim stacks.
I have not been inside our BRP Fox shox, out of the box they worked very well, and at under $400 was a great value.
All the best in your quest.