i question just about everything your 'alleged' horticulturist told you ...

conifers are trees... they never stop growing.. there is no true size ...

using the proper latin name for the bakeri ... look at the pix at the link ... i see an 8 to 12 inch leader growth ... and 6 to 8 on laterals .... and all you would do .. is multiply that by 10... 20 .. 30 years ... to extimate size ... as time goes by ...

do the same with your other plants listed ...

is this DIY ..... are you buying large .. whats your soil ... etc .. i dont know how your location makes a difference ...

maybe if you give us a pic of the location ... we can give you other ideas ...

ken

https://www.google.com/search?q=picea+pungens+bakeri&biw=929&bih=743&source=lnms&tbm=isch&sa=X&sqi=2&ved=0ahUKEwjZ_5XbjcPLAhWkxIMKHUv0BPAQ_AUIBigB&dpr=0.9

Everything presented on the market as a non-dwarf tree offered in typical sizes (and in average or normal price ranges) the growers have gotten to come along pretty fast - the more often they turn over a field the more money they make off of it. If a spruce isn't say, hundreds of dollars when a few feet tall (or perhaps less) it isn't a slow-growing dwarf that takes 10 years to grow 20".

Serbian spruce typically makes a silver-and-green narrow pagoda-like shape that is distinctive among familiar garden trees, with some individuals being very narrow. Colorado spruce is broader growing and chunkier looking up close, stiff and pokey (hence pungens). But if you want that blue coloring, no Serbian spruce looks like a blue Colorado spruce.

Also Serbian spruce can have problems in very windy locations.

i apologize if i offended.. good luck

ken