(actually 5 times ground speed, so 60kts make 300fpm)
That makes it about a 3 degree glide slope and whilst it's been a long time since I've flown a 172, that strikes me as being too shallow. Actually, now I think of it, it's probably a bit shallower than 3 degrees. In airliners we use half your ground speed plus 50'. So 120 knots ground speed down final gives a V/S of 650'/min. I won't comment beyond that as I'm not current on lighties.
You made a comment on the last page about how to get back to centreline if you're adrift coming into the flare. It's too late at that stage to worry too much about trying to get back to the centreline prior to touchdown. Sure, you don't want to drift too far downwind so a go around is the right solution if that occurs or get it on the ground a bit more quickly. If at the flare you're off the centreline then as long as you're not drifting downwind at a great rate you need to accept that and live with it. Get back on the centre line once you're on the ground.
I have one other bit of advice. There has been some excellent comment and advice from many contributors here. However you're reaching the point where it's all piling on top of each other and I get the impression you're trying to encompass all the feedback into your flying when the reality is you may not yet have the mental processing ability (when flying) of actually doing all that. If there is one bit of advice it would be to KISS. Take it right back to basics on what you need to achieve. Sometimes, listening to too much advice just crowds out the basics.
Good luck and remember to enjoy it. It's not supposed to be hard work- even when it is!