Balancing root pruning with top foliage (Alberta spruce)

[LeftHandLuke]

I grabbed a couple post-holiday discounted Alberta spruce from Home Depot and am happily moving them into training pots. The process has involved reducing the root volume by 30-40% and I feel fairly confident that they'll do okay for the coming growing season... But, I haven't cut back anything up top. On one hand, I'm hoping to grow these trees full out and let them flourish in their new bonsai training pot homes so I haven't cut any foliage. On the other hand, I'm worried that there's a ton of green stuff above ground that could die back (or worse) now that there's less sustenance coming from the roots. I'm okay with strategically cutting back some green but I do want to keep it growing strong above and below. Am I asking for trouble if I don't prune above proportionately to what I've pruned below? Is there a rough ratio? Any other tips to share?

 

[canoeguide]

Those little solar panels called needles are precisely what is going to fuel root growth and recovery. Your highest chance of success is leaving all of the foliage on the tree and doing nothing except caring for it for a year.

 

[Wires_Guy_wires]

My alberta spruce do not like rootwork.
I try to do one insult per year. I did more in the past and it's now year FOUR of still not really bouncing back.

I think you can safely wire them this fall, but for now I'd wait it out.

 

[LeftHandLuke]

Your highest chance of success is leaving all of the foliage on the tree and doing nothing except caring for it for a year.

That's precisely what I was thinking. Thanks for confirming!