I don't know about the latter, but I do know that the smaller Stihl clips are not very forgiving beyond a certain point when sliding them into place with a notched tweaker and I've had several simply collapse rather than 'give' enough to slip into the pin boss groove. Bought a bag of extras just for that reason. 'Course Stihl would have you use their installation tool which applies uniform force around the clip circumference and all but eliminates that problem. Don't know too many guys that can afford em, tho. I sure as hell can't. And there's a separate tool for each pin diameter.
Speaking of installation tools, has anyone had experience with any of the other insertion tools out there?
And one last armchair quarterback suggestion, (from me anyhow), if you don't already do it; Install the circlip that would be the least accessible if the piston was in place on the saw first, and do it before installing the piston. Much easier for that first one regardless of your method. If you can't get that one right, you probably shouldn't try the other one.