Thank you for the answer.
I may be able to save the original vines by putting in the new support structure, 50inches tall x 16 ft long livestock panels, between them. Basically, turning the supporting structure and not the vines. This way I may only loss at most 50 percent of the original vines. Have purchased 4 new young vines.
Could I start new grape vines from those vines that will eventually have to be pulled out with the front-end loader?
Could I just take the longest and healthiest branch and bury it in the garden soil and wait till it takes root to cut it off from the "parent" vine?