FLI Cameras

Unfortunately this will not work. The Alan Gee is not correcting the Coma of your telescope and will not cover the entire APS-C matrix when screwed into the diagonal

An extender 32mm long with 2" thread whould be helpful, unfortunately we don´t have such. Instead you could use a #2956220 ClickLock
screwed directly onto the OTA:
https://www.baader-planetarium.com/en/baader-2%22-clicklock-eyepiece-clamps.html
https://assets.baader-planetarium.com/media/extendware/ewimageopt/media/inline/72/3/baader-2-clicklock-eyepiece-clamps-from-t-2-to-41-2df.jpg
It is slightly too long, 47mm minus the 7mm thread from OTA, but a f/10 ratio optic like a SCT is tolerating it.
https://www.baader-planetarium.com/en/baader-2%22-safety-kerf-nosepiece-with-2%22-filter-thread.html
Now you can put on your set-up as usual and the camera and guiding camera are staying common.

There are at least two ways to realize it.

First you can screw on the OTA a #2956220 SC ClickLock
https://www.baader-planetarium.com/en/baader-2%22-clicklock-eyepiece-clamps.html
Then as an unit following parts (in the row from OTA to the diagonal):
https://www.baader-planetarium.com/en/baader-2%22-safety-kerf-nosepiece-with-2%22-filter-thread.html
https://www.baader-planetarium.com/en/baader-ufc-s70--2%22-adapter-2%22-sc-thread-(f)-telescope-sided.html
https://www.baader-planetarium.com/en/baader-ufc-base-(filter-chamber)-telescope-sided-s70-dovetail-receptor.html
https://www.baader-planetarium.com/en/baader-ufc-2%22-sc-adapter-2%22-(m)-camera-sided.html
Optionally a second CLickLock 2956220 when using the diagonal with the 2" barrel.
Now you can put on and off the UFC in one piece to be more flexible.

Second way:
https://www.baader-planetarium.com/en/baader-2%22-nexstar-locking-ring..html
https://www.baader-planetarium.com/en/baader-ufc-s70--2%22-adapter-2%22-sc-thread-(f)-telescope-sided.html
https://www.baader-planetarium.com/en/baader-ufc-base-(filter-chamber)-telescope-sided-s70-dovetail-receptor.html
https://www.baader-planetarium.com/en/baader-ufc-2%22-sc-adapter-2%22-(m)-camera-sided.html
The NexStar Locking ring is neccessary otherwise the 2" SC thread from OTA is intrusing too deep into the UFC base

Filter slider for 2" filters:
https://www.baader-planetarium.com/en/baader-ufc-2%22-(m48)-filter-slider.html
And for the 1,25er :
https://www.baader-planetarium.com/en/baader-ufc-d-50.4-filter-slider.html
https://www.baader-planetarium.com/en/baader-ufc-1%C2%BC%22-aux-filter-holder-(requires-2459113).html

I´d say to stay with 2" filters because you can use the diagonals 2"/1,25" reducer so you´re able using 2" filters
with 1,25" eye pieces. For some reason lots of customers regret to buy 1,25" filters and wanting it later in 2".

1. because the price would become prohibitive - in the range of €1000.-
2. because the filter cell would need to be ~ 12 mm high - a killer criterium for most users as there is not enough space in the optical train.
3. since lucky imaging cameras have small chips - not needing larger filterrs than 1 1/4"
4. BECAUSE WE ÀBSOLUTELY DO NOT WANT TO SUPPORT LOOKING AT THE SUN IN UV-LIGHT !!!

Please take a look at this PDF
https://www.baader-planetarium.com/en/downloads/dl/file/id/287/product/4184/faq_problems_with_filters_can_have_the_strangest_causes.pdf
and this blog post
https://www.baader-planetarium.com/en/blog/halos-viewed-without-prejudice/
where we have collected a couple of information about filters and halos.