How much space do I need to give them? They will eventually want to get 15 to 20 feet wide and about as tall unless you espalier or do other planer pruning along the wall. Looks enough like yaupon to me to think your builder probably has it right. Most of the 20+ year old ones in our neighborhood have been trained as multi-trunk trees, but have seen single trunk used nicely more often in newer plantings. Could help to know the gender of your plants before you move them - there's a small chance the builder/nursery might know. Berries on the females change the look (improve, imho) and would be nice to have matching plants, male or female, anywhere you may be wanting some symmetry.

look at T. o. degroots sprire ... look for single leader plants.. and try to maintain them that way ... they will outgrow many of the other arbs.. like emerald green etc ... height wise ... and i would diversify the planting .. perhaps the holly gal mentions ... i would also plant at the bottom ... why not .. i would go no more than 4 footers ... ken https://www.google.com/search?q=Thuja+occidentalis+%27DeGroot%27s+Spire%27.&source=lnms&tbm=isch&sa=X&ved=0CAgQ_AUoAmoVChMI59iW_ampxwIVB0KSCh3LTgG7&biw=870&bih=745&dpr=0.9

So, the Green Tower Boxwood seems like the best option. With them being slow growing, it sounds like I should hold out for 15 gallon sizes even if that means I have to wait until next spring for them to be stocked or I may be waiting many more years for them to grow large enough to be useful above the fence line. Can they be pruned into a tree-like shape with a few feet of exposed trunk so they expend their energy into growing their foliage faster higher up where they provide privacy as opposed to lower where the fence is already providing privacy? Are Green Tower and Green Pillar Boxwood the same thing?

@gardengal48 (PNW Z8/9) I ended up deciding to try to prune the leggy leader becaused I wanted to encourage more fullness and try to shape these before they get tall enough for me to need a ladder. I chopped off over half of a long leader till when I think I saw sprouts (first pic). Do you know if this is the best thing to do (i.e will this encourage the bare stems with single leaves below to also sprout branches and thicken up or should I cut all the way up to where I am hoping the bush will start to thicken up. Also I did an angled cut same direction as the last bud but wasnt sure if thats what i should do whek topping a branch? Also any recommendations for how i should trip bush in second pic would be super helpful! Not really sure what I should do since there are three leggy branches growing from one middle leader. Should I pick one to try to train as leader and cut off the other two? Thanks!