Just a tip for installing that gear box. Grab a couple bolts of same diameter as ones used to mount the drive but 2 or 3 inches longer. Cut the heads off the bolts, use a zip disc and make a slot across diameter of the end you just cut that will fit a flat screwdriver. You just made pilot studs. When installing a new drive, thread the studs into it and they will help guide and support the drive as you get it mounted. Once a few other bolts are in you just remove the studs. That’s why I slot the end of stud, just in case it’s a bit stubborn coming out and can’t do by hand. A trick I’ve used a thousand times in my 35 yrs as a heavy equipment mechanic.

Laura, as an old guy who worked and played outside a lot in my younger years, I beg you to wear hats and sun-shield type long-sleeves and pants. If you do, your dermatologist will thank you in fifty years and you will thank me (even though I'll be long gone). Also, if I thought you'd wear them, I'd send you a bundle of work gloves (the thin ones, not the awkward heavy leather ones). I want you to stay healthy and cheerful for your kids and grandkids.

I would seriously look into a different kind of Jack arrangement. Someday that one legged beanpole is going to fail and someone is going to get hurt. Otherwise, job well done!