Great plan boardmaker, I prefer a E-W screen line whenever possible; plus, I believe in direct seeding in almost all circumstances. Regal Prince are pretty wide relative to some of the "tighter" columnar oaks; if you plant on 10 ft centers, you could remove a middle tree (among 3) as the trees grow outward. In one screen situation, we planted columnar oaks to fill holes between spruce trees. Planted acorns from 3 different sources and experienced a partial disaster (if one wanted a nice clean uniform line). 2 trees display excellent columnar shape; however, one tree has leaves twice the size of the other (different parent trees and genetic transfer). 3 trees are pretty gnarly (2 display more SWO parent characteristics than col. English leading to a not-very-tight shape) ... the 3rd is just downright garish in appearance, and one died (was a very nice tree). We may plant a 30-40 foot screen using Kindred Spirit col oaks next spring; I have located a source with some of the prettist trees I have ever seen and they produce lots of relatively large acorns in good numbers for young trees. I would suggest you avoid my mistakes by planting acorns from a single source if possible; nevertheless, there will always exist the possibility for genetic throwbacks on F-2 offspring. A couple of short screens we planted using single source acorns have produced trees retaining a tight columnar shape and good growth. Another mistake I made was caging them too tight in that as they grew outward, the concrete reinforcing wire cage inhibited growth Tree was reluctant to grow through the 6-ince squares and when it did, the deer browsed them heavily ( got a pretty high DPSM). In some sense it's like girdling your tree; it won't kill it but it will get a shape with a skinny bottom to the top of the cage. I'd plant as early as you can in the spring and be sure to add protection (from deer, rodents and bunnies).
There is a way to ensure they are all columnar; however, it entails a lot more work. I NEVER plant any tree seed in containers ABOVE ground ... I believe - to do it correctly - the maintenance is as bad as caring for a 2-month old child (regulating hydration can be a pain and limit your trees growth .. it's less of an iss +uefor a tree in a jug in the ground ... less wind problems and sun induced temp increase in container .. plus evaporation issues. That said, I have planted acorns/chestnuts in gallon containers (with holes cut out of the bottom and all 4 corners )... the containers are planted in the ground before planting the seed. Space them about 4-5 foot apart to give yourself some room when digging them for transplant.
Plant your screen line and watch for 2.5 yrs (april to april to april to october) and use you nursery trees (the ones in gallon milk cartons to replace any in the screen line you don't like) in late fall when they are dormant. Good luck my friend and keep us posted. I'm betting you produce a really nice screen.