Well, first things first: The plants themselves "need" no pruning, the pruning is to meet your needs. Arbs are actually quite forgiving though, so I imagine you can reduce their size somewhat and still have reasonably healthy plants left behind. Buw what I don't like about what I'm reading here is first-they will never look as good as they do now, and second, you are setting yourself up for an endless task. Once pruned in the manner I envision you want to, they will look poorly whenever any new growth gets "out of line" with the artificial parameters you will be setting.

So I ask, are these plants multi-leadered? That is, are there more than one main stems in each? If so, that does argue for what you are concerned about having happen-a too-heavy snowload (or ice) causing them to split out. But if by some bit of luck, they are more or less single-leadered-like wild arborvitaes usually are-they will handle snow like champs.

I live in and more importantly, own land in the portion of this state where wild groves of Thuja occidentalis-the plant in question here-occur. I kid you not-I have seen twenty-foot plants bent right to the ground with snowload...bounce back the very next spring like nothing happened. So at least a part of me wants to tell you to do nothing and just see what you end up with. As far as "theyre getting too tall"....I ask, for what purpose are they getting too tall? Shading out your yard?

They look pretty darn nice just like they are now. Anything you do will lessen that appeal, I think.

i suspect you will regret ever doing it ...

as to winter.. let them alone.. and remove them if and when they get damaged ...

your dream of independent specimens was passed years ago ... and i dont think you will achieve your dream look.. but.. if you insist. give it a go .. you can always remove them later ...

ken