Hello! So about a month ago, my dog had surgery for a slipped disk, and since had regained feeling in his legs and tries to walk, but isnt strong enough to walk more than a few steps without falling over. Also the nerves that affect coordination and balance need more time to heal too. But he's an active 5 year old dog, and he needs to move! I made him a sling and some dog boots so I can hold his back end up on walks, but I think he would have more freedom with a wheelchair. It would just serve as a (hopefully) temporary tool to aid his rehabilitation. Something that will hold him up while he walks, but let him use his back legs too. Ive done a bit of research, and found some wheelchairs I like, and started building one out of aluminum. My biggest problem is weight. I tried the one I have out on him, and the balance is all off, which places too much weight on his shoulders. I think this relates to tire placement. Right now the bars holding him up are directly over the tires, but I want to move the tires further to the front, to maybe counter balance it a bit more. Are there any formulas or things like that I could use to get an idea of how exactly to do that? How far by what weight, etc? Second question: I want to put in some springs so that he actually can bend his legs and squatt a bit to pee and poop. Also that he is more or less forced to walk because with the springs, if he doesnt use his back legs, the wheelchair sags down a bit. But I want to make this adjustable as well, so that when he's tired, I can tighten something to create stiffness so that he doesnt need to put so much effort into walking. So this is what I have so far. I want to weld in a seat, and then pad it. Also, I think I will make the back wheels wider apart and remove the bar over the butt. If anyone has any suggestions or advice, that would be really appreciated. Thanks.