BIG QUESTION FOR YOU GUYS, please answer kindly,

i just gave 1 of my 3 skybolt kits to a couple of friends that i fly with. i gave it to them because i know that when i sold my framed up version some 15 years back, one of my buddies said "yeah i wanted it, but never had the cash"...............so i feel good about giving things to others...............but i did ask that they had at least an FS.91 for it.
now i'm told they are going to install an OS fs .70..............Doh!!
i told Marion (he's the guy i know best and gave the kit to) that a .70 is not enough.....Marion tells me, "probably so, but Bobby just wants to putt around and make an occasional loop"..............Doh!! again (Bobby is who Marion gave the kit to, as i they are closer to each other).

i just can't see the OS .70 doing the job, but give your input please.