Well, some of you may have seen my thread about USO spotter mounts and such and that kickass LRR-104 Mk5 LRF I scored. I have a unique way to do this, I doubt I'm the only one to do it but I figured it out on my own so here it is:
What I ended up doing was mounting a spotter to a custom mount (if you're using Leupold or Hensoldt, you have tons of choices!) a member here made for me. The spotter goes on the bottom, LRF on top and a PEQ2 on the side. The LRF has a range of over 6 miles.
So my intention is to take it out to the mountains where I have the range and setup the tripod and get it all stable and set the LRF up on a specific target at the extreme distance it can measure, being sure to select a target that can't be confused with the background, ie, you need to know you are definitely on a specific target. A reflective hanging plate would be ideal.
Then, just wait for it to get dark, then using a PVS14 and the spotter (or perhaps a rifle scope with NV) and adjust the PEQ's laser onto the target.
Now, when you use the spotter with the PVS and find a target, you just tap the LRF and get the reading without actually aiming it. The PEQ will only be off by a couple inches proportional to the distance and decreasing with range, which won't be a problem.
The PEQ is now slaved to the LRF. Line up the illuminator to the laser and you've got a day/night spotting setup. Ideally you want a PEQ with a high enough setting to actually mark the target at that range and also illuminate it. Now you can also spot for another shooter at night while marking and ranging targets simultaneously.
You can do this with any spotter, LRF and PEQ combo setup within its limitations.