Im not sure I follow what the issue is. The top and bottom plates can still be one piece and can be cut to the shape I outlined.
If I was making this for where I work I would model it, rotate the cup a few degrees and get the new cut profile that would simplify the compound angle for arm-to-cup interface.
The 1/8 clearance I was referring to is distance to the spring at full drop....thats not enough to account for vehicle tolerances..... I wouldn't want my arms hitting the springs while offroading.
Right now it looks like the uniball is maxed out at full droop.... I wouldn't want the uniball to be the suspension limiter; Let the strut limit full extension.
To answer your question on if I think my suggestions are "worth it"..... for an arm thats a premium price over the JBA arms id say yes.. an emphatic yes. Leave no question in anyones eyes that your arms are merely equal (if not currently inferior) to a competitor, especially an established competitor like JBA.
JBA recently redesigned their arms to optimize them for lifted WKs. Pretty sure I emailed the link to jeepforum for you to check out. He made 4 or 5 iterations to try out until they were perfect.
Just an FYI your customer is running a double-stacked lift that isnt generally recommended. When you get it back in measure the distance from center of hub to bottom of fender.... most 2-3" lifted WKs measure about 22.5".
Edit: do you have a 3D model of your arms? Id be happy to mess around with it.... you wouldn't be able to use the file since I only have a student version of ProE at home (I get a license every year as part of a mentorship I do) but I could at least get some better screen shots than ms paint lines lol