Measuring for rear shocks

I've watched a handful of videos on how to measure for new rear shocks but am not sure on best way to go about this.

Truck has a 4.5" lift currently. Soon will be replacing front with new taller heavy duty spindles for the 5" lift of same brand, TUFF Country and ICON extended travel coil overs. I didn't see the need to buy the rear resi coil overs but want the truck to match front to rear brand wise. Icon said they could custom build non-resi for the rear I'd just need to get them measurements extended, compressed and maybe static...maybe he just said the first 2.
Anyways, question is if the front goes up a hair with new c/o's and spindles I don't think I can just obviously take the specs of the current rear shocks and go off that, can I? I'd like this to be level or just a slight rake. It sits pretty level now but guessing that will change when the front is installed.
They made it sound like I couldn't just throw in a shock that was close or within the same range/close to something they already currently make. I'm no suspension guru so...
Truck is just a daily for the most part, just don't wanna cobble something and it bite me when I could've done it a better way from the git-go..

My brain is telling me I need to wait, install fronts, set it level by jacking it up then get the measurements to order custom rear shocks.

 

Nevermind. Thought about it answered my own question