Nancy and Heather,
This discussion reminds me of how some medications are used "Off Label" as we adapt what is available to suit our purposes. I've been using ruler work on my domestic machine for over 4 years now and it all started with using a different 'toe' for the Janome convertible free motion foot set. That 'ruler toe' was labeled for use with one specific machine, but it fits ALL the Convertible FMQ sets for all Janome machines. (And difference versions of the foot combination have been used on many other brands' machines including Bernina)
It took over 2 years before I got Janome America to pass official word that this was an acceptable use for what had been an obscure accessory. That was in 2014. I still have students/blog readers tell me their Janome dealer says it's only for that one machine.
Ironically, as a Janome user, I am often in awe of all the great feet that Bernina has. I was really hoping that the #96 foot was going to be the official ruler foot for Bernina especially as my Craftsy class for ruler work on a home sewing machine goes live in a few weeks.
I'm glad you've found a foot that works for you as long as you follow the precaution of putting foot down before dropping the needle. Make sure that your foot height won't allow the ruler to slip under the foot, or choose thicker rulers (using 1/8inch thick rulers like a rotary cutting ruler can be risky if the foot is too hight or the foot hops) and above all--- have fun!
Amy
www.freemotionquiltingadventures.com