I myself, use 1 space, 1 finger. If someone asks me should I practice fr? I tell them, 1 finger gives you what you need. But fr is an style. Fortunately you can do a scroll with 1 shot of rope in the same time (or less) than going that space with million shots (doing fr or whatever).
To answer you Dub-c, in drum example,
by practice if 1 hand CAN do X strokes on the drum, if you add the second hand, you can get a result of 2X speed.
On the keyboard, it is different. Theoretically you must be able to. But the point is, does your keyboard accept those many 'shots' and send them successfully? Even if it does, then you're gonna have wasted rope shots. Because many times it happens your rope is not yet attached to the wall, but you send another stroke to the game, which will be refused by game.
For example, try doing a wizard when your rope is a bit longer than it should be. If you do 3 fast strokes on the rope, the game accepts 2 of them and third one fails, so will your wizard. Other than that, how many times have you seen someone fails to do a shadow? they do the 3rd shot much fast that 'it doesn't count' by the game.
You are right though, the 1-finger tap is faster than 1 of each fingers in fr (In keyboard example)
even if someone have the ability to do each of his fingers taps as much as the other one, he gotta slow down to reach the game level acceptance of shots otherwise he'll have tons of wasted shots.
But why 'fast tapping' is more important than the tapping output result itself? Why do you care
HOW people reached their fast taps? (Obviously my point is other than using-programs)
It is like caring how your car engine is managed. It is using 8v straight? or is it two 4v in parallel?
Other question to me is, I've never heard people calling moded-space cheating. Why is that? I've seen people call many styles of tapping cheating but moded-space?
We use different equipments. So basically we start off different. My space bar sensitivity is different than Ramone's space bar. The amount of space I have to push my space to get a shot is different than others. We all have a different roping performance with other people's keyboard!
The only way to solve the 2-space argument is that T17 enable remapping game control keys and put a link 'Assign another key to do this action'. e.g. 'Add another key for "space"'.