I had the same problem with my one y.o pointer recently. It was very stressful for everyone because on-lead walks do not make him more relaxed, the exact opposite. We would take him off the lead back in the house and he would zoom around the room, leaping over furniture and knocking over the children in the process. In the end, I had to get him sedatives - we got through it though. I would be reluctant to take off the cone - you don't want the wound taking any longer to heal. My pointer loves sprinters so I really hope it goes well.
I took the cone off after the first day because mine hated it so much and was rubbing the edge of it against the stitches. We watched him closely and he didnt bite the stitches. Failed totally at keeping him calm though he was bouncing round like a loon
Yesterday we had our first dog emergency. Our Springer got caught in a stray bit of barbed wire fencing (I'm going to go back today and cut it down) in the woods leaving her screaming and with a badly cut front leg and shoulder.
After being treated at the vets she now has a cone, bandages and a funny vest thing covering everything.
She is this morning fine but needs to be kept calm (!) and no off lead walking until stocked are out possibly 10 days+