I'm thinking of planting a hedge row of Green Giant Arborvitae. I
want to plant them tight (3 foot on center), because I don't like the
V-shaped gaps I've seen on other Green Giant hedge rows planted to the
"recommended" spacing.

My other plan is to keep them sheared to a rectangular envelope 4-6
feet deep and 12-20 feet high.

Does anyone see any problems with either of these plans?

Thanks.