On clearance, I bought what looks like a 2 year old red flame seedless grapevine on a whim at the box store. There are two "trunks" growing from a pruned woody fork (1st yr growth?).
I have a small yard. After fretting over the perfect location at home, the best spot for sun, air and drainage will require the mature width to remain about 6-7 feet wide. (There are young fruit trees on either side that will eventually grow wider, hence limiting the grape width. The dwarf citrus tree on the west side can be kept low to allow sun to hit the grape).

Can the cordons be cropped to 3' on each side permanently?

Thanks in advance for any advice!