Not that it matters but plenty of divers could do a multi-level dive with 140' max depth and 60 min total dive time. If I can do it with a 100 cft, quite a few could do it with 72 cft and have more than 500 psi left over. Some small women I know could easily do it with 63 cft!
I don't think the question is whether you can do a simple descent to 140' and ascent with any of these tanks. If this dive you suggest is not a bounce dive, you may want to become acquainted with the concepts of "rock bottom" or "minimum gas". Moreover, what exactly was your plan if you had a catastrophic failure (extruded tank o-ring, first stage failure, second stage freeflow....) at depth? CESA from 140'? I don't think I could do it....... Or were you planning on sharing your friends 63 cu ft tank? Here are some numbers for you:
Gas used for descent: (assuming a very low SAC of .5 cu ft/min) 4.5 cu ft
5 min at 140': 13 cu ft
1 min at 140' to share gas and sort out problem but now with two people breathing quite a bit faster--SAC now 1.0 cuft per min: 10 cu ft
Ascent with 2 people at 30 ft per min: 30 cu ft
3 min at 15 ft (you were at 140' afterall) for people: 9 cu ft.
Total gas used: 66.5 cu ft......... I believe you started with 63 cuft.......
Which one of you were not breathing for the last few minutes?
This is the reality of your gas plan.
Were you planning on not doing a safety stop after a dive to 140'? Were you planning on a lower emergency SAC rate? Were you planning on no emergency?
I am not trying to cut you down. I am sharing with you the simple physics of the equation. Everyday people do this dive on single AL 80's and have no understanding of the numbers. However, with this awareness, you have to knowingly make some decisions regarding risk. What you chose to do after that is entirely your choice. You and everyone else simply deserve to know what is involved in the risk equation.
Again, this is not an attempt to flame you.