Fastback:
I guess with what was meant here in the threads by lowering collective is collective fully down. However, as we both know, if you are flying at e.g. a 100 KTS and fully lower collective while simultaneously flaring the R22, God bless you, because the RPM will be through the roof pretty quickly.
As for your speed recommendations, maybe have a quick look at the R22 manual or speak to instructors that have really taught in the R22. The recommended glide speed is 65KIAS.
And yes, you will live through it, even if you have less speed. In fact, you can even do a no flare auto in the R22/ R44 by holding your speed consistently at approx. 40 KIAS, RPM top range and just applying full collective as you approach the ground.
Not that I want to give anybody any ideas, but it works.
Anyhow, the speed in the R22 only matters as you are getting ready for the flare, and the 65 KIAS seem to be just a good value. Any slower then 55, you may be missing the A/S for a good RPM value, any faster then 70/ 75 KIAS before the flare and it becomes quite tricky to control the RPM.
You are perfectly right to say that you can control the RPM with collective during the glide, which you almost every single time have to do, not only in the R22. But for student pilots and freshly rated pilots the idea is "KISS" keep it simple and stupid.
Establish a glide as consistent as possible and use the free time to think about what's next.