Thanks mate, the hardest part of this post was delivering the information in an understandable way, meaning I know what I know, but explaining it properly is maybe beyond my skill.
Knowing range at greater distances is critical, although a guestimate can work and there's techniques designed around that like bracketing. But there's nothing like a good accurate rangefinder and the Sig one you have is great.
You're right on the cheat sheet (DOPE) and long range shooters will always gather it, record it and pass it along.
I'd not want to get caught out without a rangefinder, but it happens, and when operations need to continue unabated this mil-ranging formula and process works flawlessly.
Thanks for your comments and yep, as always: One is none and two is one.
All good operators know this. 😉