I think your last sentence says it all really - when to close the throttle.
I find that the "low inertia" of the LSA 55 Jabiru makes it want to cease flying after the throttle is brought to IDLE maintaining Vref to the flare /round out; just like a PA32. So you end up with a positive touchdown. Some of my colleagues will leave a trickle of power in the Jabiru to get a greaser, which I guess is OK for them. I've seen others do a botch job when a sudden gust and that trickle of power ballooned the aircraft, into a semi-stalled drifting situation with ineffective flight controls.
Read an article called Great landings vs. Soft Touchdowns in P-3s in the [COLOR=darkblue] U.S. Navy's Approach (May '82) Magazine which made me think about what constituted a "good landing".
New P-3 pilots joining a squadron suffer a rude awakening when landing on the mains; at the proper speed; at a specific point and on centreline with a slightly firm touchdowm is not considered a "good landing".
To avoid ridicule, the P-3 pilots learns that he can make consistently soft landings by landing flat; at midfield with power on to keep the crew happy!!!! What happens when there's snow, ice, water on the runway the author asks.
I wish I could share the last paragraph of that article with my mates. I reckon the principles provide sound advice. I quote:-
It is a true confidence builder when a pilot can make a landing nose high; on centreline; in the first 1 000 feet of the runway, with zero thrust at touchdown. When he can combine a "great" landing with a soft touchdown, the multi-engine pilot will experience a feeling so good it's almost indecent. And do you know what the best part of it is? It'll be a SAFE LNADING with PROPER PROFILE TECHNIQUE.