I'm concerned about the final size, although it's possible that by the time they outgrow the space the house will be sold to better neighbors (and we may not be here, anyway!)

I wouldn't take that mentality. Look at the mistakes the previous owner/s made and now you have to deal with it. Instead of a beautiful mature landscape you are dealing with the mishaps.

I'll admit I didn't spend much time on your design post but I'll offer my quick two cents regarding selection.

Drainage is critical for conifers. Pines will suffer but some spruces will be ok. You may need to plant high to aid in drainage.

Generally speaking Picea abies and mariana tolerate moist soils more so than others. You'll also want to note that many grafted spruce are on Picea abies root stock so you get that adaptability.

There are many narrower cultivars you can select. For example Picea abies 'Cupressina' is a very popular and narrow selection.

There are many nice selections of Thuja that you can look into as well.

Perhaps give us more info on spacing (what you have to work with) and direct location directly in this post to get more solid feedback.

Those are hemlocks are doing poorly due to their placement. Not sure what the person was smoking when they put them there. From a size and adaptability perspective.

i often see norway spruce in yards here in new england... they are massive and imposing (laterally also). here's a good site for ideas.

Here is a link that might be useful: Sun Valley

Thanks to you both for your thoughts. I guess this was my real implicit question: Is it possible to arrange a handful of Norway Spruces (or similarly shaped/habited conifer) such that they can be strategically removed as they get older and fill in? I'm sure I'm not the first person to have that idea, but that doesn't mean it's not hare-brained. Perhaps this isn't what I should be focusing on.

I don't like the look of truly columnar conifers. They seem like overly formal mutants to me, although of course trees than have grown slenderly due to spacing can be quite attractive. It also calls to mind the perennially scraggly looking arborvitae. Not sure if it's deer, cold, wet, soil pH, or what, but NONE of the many in my neighborhood look good right now. The only ones that don't look tortured are wrapped in burlap, and that's just not how we roll in our household.

Based on what you're saying, a spruce does seem like a good choice, although the options through that excellent Sun Valley website are a little overwhelming, in part because their search engine is a little frustrating.

I was also having trouble locating sellers for some of the P. abies that looked interesting, and other sellers have variants that weren't on the SV website. Is there a particular seller you'd recommend?

if you cant find something that fits.. w/o having to replace them all the time.. you arent trying hard enough ....

link below to intro to conifers ....

most of us.. get our plants mail order.. or special order ...

you are NOT going to find the good stuff.. at bigboxstore.. or gratuitously at the corner nursery ...

ken

Here is a link that might be useful: link

true again, yet for a 40' span that you basically want as a natural fence i'd want to start with at least 4 foot specimens if choosing conifers. i recd that site cause they seem pretty good with pics and eventual sizes. i envision a staggered (irregular stagger) border of blues ie moonglow juniper, hoopsii spruce, witchita blue juniper, greens like korean fir and maybe a frasier fir or serbian spruce... even an emerald green arborvitae, (all of which can be hand selected from a local nursery, i actually got several from home depot((aahh!)) with good size and vigor at good prices). ... then in front of those mix in a few online purchases like silberloche, korean fir aurea (yellows), or spring ghost, dwarf alberta spruce(get those anywhere)... pls excuse my lack of proper naming ettiquette but you get the drift. what a beautiful living fence it would be!

space then for eventual widths but you are correct,... farmers who plant wind screens with large conifers often space them 8' apart for starters and down the road, remove every other one. the land is your pallete :) it all depends on the end result You picture, and your budget.