Uhhh...Pat? I've got a question for you...
That's an I-beam running the span of your garage that the chainfall is hooked on, right? It looks to be a 6" beam. Is that used exclusively for shop purposes or does it carry the weight of space above the garage? I only ask because I wonder about the deflection loading on that beam with the weight of the shell added to it right in the middle. That's the point of maximum loading for the beam, and seeing as how you'll be *under* the shell I just had a little concern.
If the beam was installed exclusive for this purpose and doesn't carry any additional weight from overhead then that's a different matter.
Is there a reason you don't use the lift with jackstands to support the shell while working on it?
Not trying to be critical or contrary, I just look at the potential consequences of failures on about everything I do...