You need adaptor for the ITL200 which has some oddball M38 threading:
https://www.thorlabs.com/thorproduct.cf ... ber=SM2A20
For Mitutoyo, you can use Thorlabs SM2 > SM1 then SM1 > M26x0.706
That's what I use.
https://www.thorlabs.com/thorproduct.cf ... mber=SM2A6
https://www.thorlabs.com/thorproduct.cf ... ber=SM1A27
To get the 148mm flange distance, you want one variable tube to finetune it.
Then thorlabs says the optimal distance between the tube lens and the objective is 70-140mm. I'm mounted the objective with minimal distance, didn't see much of a difference.
You can use a couple of these to mount the setup on a long arca-swiss rail: https://www.thorlabs.com/thorproduct.cf ... mber=SM2RC
These work well too but more expensive: https://www.thorlabs.com/thorproduct.cf ... mber=SM2TC
Here's the ITL-200 setup on a Z6:
To answer your question, yes the variable tubes are a requirement.
Between the SM2A20 which houses the ITL-200, you need various tubes to reach 148mm minus your camera's flange distance: https://www.thorlabs.com/newgrouppage9. ... up_id=3383
I have two each of thin couplers that features male>male and female>female threads. They have tubes without external threads and ones without internal threads which makes it possible to apply flocking adhesives. However I still suggest the ones with threads, you can just roll flocking material up and insert them into the tubes.
Note that the ITL-200 sticks out slightly, about 4.6mm or so, so you actually want about 153mm minus your camera's flange distance between the sensor and the ITL-200.
If you're going to buy these expensive Thorlabs SM2 stuff, I see no reason to buy the RAF adaptors when Thorlabs offers everything you need.
The prices are similar. Thorlabs are sometimes cheaper, their SM2>M52 adaptors are $21.54, Raf charges $24.95, Raf charges I believe $5 for shipping, and it takes at least 2 weeks. I just looked at their website, seems like shipping would be messy due to the virus.