@nmstough Can you possibly take some photos of your setup? That may help community think of ideas.
What’s limiting vertical movement of upper section of pipe?
Sorry for your problems. My flow meter is arriving today and I plan to install quickly. I hope I don’t run into unforeseen issues either. The plan seems straightforward. 
My wife is already rolling her eyes at me since she’s convinced I’ll also hit a snag and have no water. 
I dont know but after I inserted the lower section of the flow meter contraption onto the lower pipe I could not lift the upper section of pipe over the top of it to get it into the SharkBite fittings. There just isnt much “play” in the pipe and of course I didnt want to bend the pipe or create a big problem out of it.
I uploaded a pic but it seems one of the moderators split it into some other post.
@nmstough, I haven’t come up with any good alternate ideas. I would look at how to remove the ball valve section directly after the back flow and then find a way to replace it after flow meter is installed on vertical pipe. If you can get it to fit, you could replace existing ball valve with a SharkBite version along with a fitting to back flow. Fit and cost are the biggest concerns.
I appreciate the suggestion but doing all of this plus the fittings attached to the flow meter is just as complicated as redoing the whole exterior piping of the irrigation system. This was supposed to be a DIY project and not to cost hundreds of dollars. Reading the original product description gave no clue about all this. Caveat Emptor.
Still waiting for Home Depot to get them to my store. Ordered a full week ago. Apparently they are in Ltd qty and only have a few chain wide. Also they do not ship direct but use their internal shuttle to move from store to store. Mine have more frequent flier miles than I do. So stupid. Rachio needs to stock and ship with meter based on pipe configuration. Well. If they ever ship mine anyway. Credit card was charged a month ago. Bout ready to ship email sent to me weeks ago…zilch.
I found that supplyhouse.com had a lot more in stock and with considerably better prices than Home Depot. And no sales tax either.
Wow. You aren’t kidding! Thanks.
Where do you live? Is there an irrigation supply house in your town? Most of the wholesale irrigation houses sell to homeowners. I never go to Home Depot or Lowes for irrigation parts.
@robertokc OT, but … We get almost everything from Home Depot. The selection is great, the pricing is reasonable, they are open late, and their people are Always helpful and friendly. We found Lowes simply has different items. Like Home Depot has everything we need for 3/4", 1/2" and 1/4" systems, and Lowes has fittings and tubing for 5/8" … which I didn’t even know was “a thing” until I saw it. I highly recommend going to both of these stores to understand their offerings, and everywhere else that’s local like Ace Hardware, Ganahl, Menards, or whatever you have available. Knowledge is power. 
Since I am in the irrigation industry, I deal with irrigation professionals at a wholesale irrigation supply house. I did recently buy some Pella windows from Lowes, however.
Follow-up to this topic: I waited a while and my flow meter arrived sometime last month. It seems to have been re-engineered. Both in and out connections are 1 inch PVC. As noted earlier, for residential we need 2 x 3/4"F-1"M adapters to lead in and out. I’ll be doing this soon. Sooooo happy that this won’t require copper fittings, expensive parts, or a certified plumber.
Thanks Rachio!
Nmstough, your back flow preventer or pipe going thru the wall usually makes the upper pipe immobile. You may have to dig around and below the bottom pipe to allow it to move.
As far as the 1”copper sprinkler tubing it is used quite often where backflip preventers are required by code.
Not following why you have 3/4" pipe. At most it can only flow 8 gallons per minute, which is not enough flow for an irrigation system.