Green Spire grows about 8" to 12" a year for me in Northern VA. But we probably have more rain and humidity than you.

I wouldn't expect to see that sort of growth immediately and especially in a dry climate like Utah. The good news is that both forms are immensely prunable so easily kept at the size YOU want!

Another question on the euonymus, should I treat with a systemic to prevent scale? I don't normally use pesticides as I'm lucky enough to live in a climate that doesn't have a lot of pest or fungal issues. My garden is pretty well filled with pollinators and so I don't want to harm any of them, but the bed in the photo is separated from the rest of my garden so? I don't even know if scale is an issue here or not.

Nope. Don't treat until you know it is a concern. IME, Euonymus fortuneii cultivars seldom ever develop scale........the E. japonicus could but scale is not uniform in its presence. For example, you rarely ever see euonymus scale in the PNW - may not be very prevalent in UT also.

i find manhattans the hardiest shrub and i like all euonymus as easy to take care of. low maintenance, basically plant them and water them once a week the 1st year and all you have to do is watch them grow and keep them trimmed if you so desire