What species? DBH? Taper?
You have a basic monoculture plantation that has value and reflects past investment. Why not treat it as an investment and choose the best way forward in those terms? Within that framework, the question is "Is your best alternative use ("foregone use") for the same 'bare-ground' more or less valuable to you in context of your preferred time frame?"
So, to assess the value of this stand you'll have to decide what ecological benefits the species confers (easy research) and what products it can yield.
In Montana P. engelmannii is the preferred house-log tree because of its high tensile-strength:weight ratio. Light strong house-logs that have relatively good insulating value. The old-timers would set down a course of western larch (rot-resistant) and build E. spruce on top of them.
Personally, I use rough-cut 1" spruce boards around the site for everything imaginable because they're so freaking light. They aren't strong boards, and I wouldn't use them structurally.
And, they can make beautiful trim.
After you evaluate, if you choose to keep the stand for future products, then you'll want to do some thinning. Don't worry about retaining the euclidean pattern. Spruce tend to clump in natural regeneration. Pick for quality and retain the best/healthiest. If you are planning to harvest in the future for timber, invest the time now to limb (at least 10 feet up). (We are talking about a monoculture in rows, after all.) You'll have stronger trim and boards and fetch a better price.
And, I would plant every imaginable shade-tolerant, acid-tolerant tree, shrub, vine and herb I could get my hands on in the understory and find every source of local mycelia and mushrooms I could get my fingers on (esp. from old stands of the same species) and start inoculating. And look around at some olders, mixed stands in the area that includes your spruce species and see what likes to grow with it. Guaranteed you'll find evidence of a mycorrhizal relationship. Plant those species with some borrowed mycelium.