I did the MM rear upper control arms also when I recently did an overhaul of my rear suspension. Best bit of advice: GET THE MM INSTALLATION TOOL! No joke. Especially when it comes to tightening the inboard nut next to the melon. PITA for sure! Key to minimizing your frustration level here is the accessible angle you create based on lifting the rear end. I think I probably did the sequence backwards. I installed the forward mounts first then tried to finagle the rear mounts in and , like I said, in hindsight believe the installation would have gone smoother if I had installed the rear mounts by the melon first. Rookie mistake, but hopefully this is good advice and others can learn from my mistakes!
Also, if you have a rear sway bar... remove it for the duration of the RUCA (and LRCA if you’re doing them at the same time like I did). It gets annoying working around and past it with the jack and getting tools in there to crank on this stuff! Reinstall it once everything’s back in place but before you tighten everything down for good. Why before tighten? You’re gonna need the wiggle room to get that puppy back in there properly and with less “creative ingenuity” than I had to use!
Lastly, measure or eyeball and commit to memory the gap on each side of the ends of the RUCA’s if you’re a masochist and plan on getting the RUCA’s that require you to install “the rubbers” as I like to call them. Or, you can save yourself A TON of aggravation and buy them preassembled (in which case you won’t need the MM Installation Tool). Totally worth it to buy them preassembled. Trust me on this!
And lastly... a sidebar:
I’m not familiar with “double adjustable“ RUCA’s. We might be talking about the same thing that I installed...And my unfamiliarity with the part! But all of the above still applies.
If you’re working on the ground with jacks and stands, it’s a son of a gun getting up and down 100 times for tools, adjusting height, etc, so get help if available. If you are fortunate enough to have a lift... I envy you! That’s all I can say!!
Good luck. It’s a job and a half, but I had a great sense of accomplishment once it’s all installed, back on the ground and all that’s left is the height adjustment.