Hand breed! Safer for your mares, babies, him, and not to mention you. I would see if someone else can't come out and help you and your hubby. Someone will be needed to hold all three horses, including foal (baby should be held near mares head, so she can see baby. I would recommend hubby right now, due to his injuries- this should be the easiest until he's healed enough to handle more).
I would also contact his owners and ask if you can use a chain when you hand breed him. Let them know your concerns, and the problems you have had so far.
My stallion has only been hand bred. I chose to do it that way, as I did not want anyone hurt, and I prefer to know my breeding dates for sure (just in case he wanted to be sneaky about it).
I use a chain on him ONLY when he is going to be breeding. He also has a special halter that is only used when he is teasing/covering a mare. We also only tease/cover in one place. He KNOWS when he's gonna get a mare... and when he's coming out to work. He's not hard to handle at any other time. He's very sweet, and gentle. But he's a stallion, and he does know it.
He can be very "studdy" when he's breeding, and since I am not physically strong enough (due to permanent injuries) to make sure he cannot hurt me, the mare, or himself while breeding. I spoke to a very experienced trainer. She recommended using a chain, and showed me the right way to do it. Since he's boarded on her property, I am instantly corrected should I do anything wrong to "our" baby boy!
So far it's worked very well. No one's been injured (badly, I've had my chronically dislocating knee pop out a few times, and been stepped on by both mares and him, but no lasting damamge done), the mares are bred, he's easier to handle, and he's not so concerned about breeding all the time. The chain is what really made it safe for me. If need be, I can pull him off a mare, where before I couldn't, as I just was not strong enough on my knee (it would pop and collapse... and yes, I did fall. Once on him while he was trying to service the mare. Shocked the heck out of both of us, but since he wasn't aiming right, I did get my wish to get him off so he could try again. I'm lucky my boy is smart enough to realize I needed help getting back up, and stood still for me).
And please, don't flame me for doing the best I can with my horse. I know I need to get my knee fixed. However, until I can get it fixed, I just have to muddle along the best I can. This is one of the reasons the two mares we are breeding this year got sent out.