I don't know how helpful I can be but I will try. If you can take gravity out of the picture on truly bad days. If your baby is crying make sure u are sitting and slide him into your lap. I know this does nothing for the crib except to get him as close to you as possible before you lift Jack. I started spending more time in the floor or play room with my oldest son, because he was very heavy, he never lost a single ounce of weight. I also dressed him in overalls quite a bit, there is a lot to get a grip on baby osh k'osh. They were more for my benefit, I put my arm through the back of the straps to reinforce my grip on Steven. I also used myoflex, or blue stuff I rub it into my hands, and slid cotton gloves on, and wrapped my hands in warm towel from the dryer, skip the dryer part if you use
blue stuff(actual name), it makes the heat too intense. You might try a teenage helper, or a part-time sitter. Just to give your joints some ease, so he can be handed to you. I never did it , but I know people who did, and it worked for them. Hopefully some others on here will give you better advice, my problem was my grip and lower back spasms, I had to buy a support belt to help reinforce my lower back. Look for compression gloves also, I don't know if that is the proper name, but they do work to keep your circualtion going and cut down on soreness. I don't know anything that helps the shaking in your hands if you are troubled by that. I wish you the best of luck,a nd congratualtion on having what sounds like a very healthy baby boy!