Jerry,
While I do not own a Stronglight 107 triple, I have some info that may be useful to you.
Wheelsmith machined threaded holes in my Campi NR cranks to accommodate a triple inner, using the also-in-Palo Alto Avocet inner rings and bolts. The Avocet inner CR bolts have a standard 6 mm x 1.0 pitch, just like the mid-1970s Campi NR brake adjusting barrels and a similar-vintage Peugeot/Weinmann centerpull brake bolt. (Nothing like having lots of miscellaneous parts handy to cross-reference! :-)
A simple test with any 6 mm x 1.0 pitch bolt (preferably alloy, out of concern for your Stronglight 107's threads) will tell you whether the Avocet bolts will work.
(I'm currently using my NR cranks on a Peugeot UO-18 mixte, but without the inner ring and bolts. I thought about putting stainless steel 6 mm bolts into the holes to protect the threads, and also verified the "standard" metric 6 mm threading using the parts bin at my local Ace Hardware store.)
I hope this helps.
Jon Spangler (who is still waiting for the first coat of drywall mud to dry on his wall patching project in Alameda, California USA)