Sorry, missed this thread yesterday. I have 2 radiae and one VSO ("Vampire") and have also had a RAPTAR.
All of them work fine as range finders. In fact, that's why I sold the RAPTAR as it didn't seem to offer any benefit over the Radius and yet cost considerably more.
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As to using with a Trijicon Mk2/3 thermal (or any thermal) ... here's my "night spotter carbine" ... i.e. a night spotter with a barrel.
That's a mk3 60mm on top ...
And the Radius is on the 9 o'clock ...
Here's the steps I used to zero the radius to the thermal reticle
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01 - Setup 5.56(10.3) on RRS tripod
02 - Setup 7.62(22) on Manfrotto tripod just to the right of the 5.56(10.3)
03 - Aim reticle of mk3 60mm on 5.56(10.3) at center of mineral feeder at 415yds.
04 - With PVS-14 on rear of NF scope, aim center of 7.62(22) reticle at the mineral feeder.
05 - Turn on the radius aiming laser.
06 - Adjust the radius aiming laser so it is pointed at the mineral feeder, use helmet mounted 14 to get into the ball park.
07 - Keep checking the 5.56(10.3) to make sure the center of the thermal reticle is aimed at the center of the mineral feeder.
08 - Fine tune the Radius on the 5.56(10.3) by checking on the 7.62(22) with the 14 behind.
09 - Once the Radius on the 5.56(10.3) is zeroed, test several known distance targets. Aim the 5.56(10.3) thermal reticle at the target and check the range. Repeat steps 07, 08 and 09 if needed
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This ^^ is the one person process ... there are other ways to do it, but this way works well with one person.