I'm reading a lot here about approach speeds. To finally solve this for a pilot depending upon an indicated airspeed to establish a good approach, I'll use a sticky note paper. He can write it on that paper if he likes, but ultimately, that sticky note will be used to cover the ASI anyway.
You're not flying a 777 with an air data computer for your SEP circuits! There are many small errors in the indicated airspeed of light aircraft, so by the time they accumulate, they could be adding up to 5 knots effect, plus or minus. Calibrated airspeed, instrument error, a pilot tube out of position, a static port with a nearby defect - could all sum up to a large error. SO, if you'd like to glance at the ASI on the way down, okay. If you're going to fixate on it, you're doing it wrong.
200 feet back of the threshold, and 30 feet up, I don't really care what your airspeed is, as long as you are able to control the aircraft's speed so as to achieve a suitable flare entry speed as you cross the threshold and an appropriate height. If you want to neatly slip off the 5 knots you carried for the wife and kids, or the gusty day, at the last moments, go ahead. Just enter the flare at a suitable speed (without having ballooned to do it).
Though not so good with the wife and kids actually aboard, when I'm flying something new, or changed, I'll often do a few stalls before I land. Not the stall where the nose drops, and the ground rushes up as I "recover", but just to the point where I get whatever warning is provided, and I can FEEL CLmax. I pull back a bit more, and the nose does not come up more - I'm there. THAT is what I'll be doing as I complete my flare, with the expectation that the landing gear is inches off the surface. The indicated airspeed will not be a factor in this at all, as I will not be watching it anyway.
"Modified". Yes, some wings have modifications, which may affect stall "speeds". Pilots must make themselves familiar with these affects on the aircraft they fly. They can be considerable, and they will affect how the aircraft should be flow at flare entry. I offer the following example:
A C 182 amphibian I fly has 300 HP, a STOL kit, wing extensions, VG's on the H stab, and flies at a gross weight of 3350 pounds (rather than 2950 for the standard 182). It really is not a "182" any more. There are a number of flight manual supplements applicable to this aircraft, some with speeds, but none which resolve the sum of the speed changes - so, I'm a test pilot. I have tested. I have found power off stall speeds as slow as 54 KIAS, power on stall speeds as slow as 34 KIAS, and certainly established that a suitable gross weight glide speed is 80 KIAS.
So, working with those numbers, what's your "approach" speed? Well, let me tell you, if I'm right seat, your approach speed is 80 KIAS, by 75, I'll be telling you to lower the nose. But, I know that when the nose is raised, that plane slows so quickly, that one can approach at 80, cross the fence at 75, gently touch 200 feet down the runway, and coast neatly to a stop in about 1000 feet of runway - that's just the way that plane flies.
Consider more how the plane wants to be flown, and less what the ASI is indicating. Feel for the stall. If you feel that you have not yet perfected your sense of stall awareness, and the wife and kids aboard are preventing your practicing to feel these sensations around the stall, you need to fly some more solo or dual with an instructor in that plane. These pitch force sensation, which give you a tactile advance notice of the aircraft's progress toward the stall are about the same for any GA aircraft, and they will guide you well through a good flare - if you feel for them, and take the time to follow them through - before you touch the ground!