You can judge you are very close to the runway surface, but is it 1 foot or 4 foot. I am talking about the last 2 - 3 seconds of the flight ... which determines whether it will be a greaser or a landing you can feel (firm)
To be honest I think that you might be being a little hard on yourself. You are very unlikely to be landing the aeroplane from 4ft up. If you were, then you'd have a teeth shattering bump, and you'd unlikely to have been allowed out solo.
Given that you're a licenced pilot and seem to be looking to refine your landing rather than learn how to land, then I would suspect that you're very unlikely to be dropping it from anything more than 1.5 feet. Even that would not be doing your ego nor your passengers nerves any good!
So you're probably judging it much closer than you actual suspect
Of course where judgement is concerned it's like parking a car. The more you do it, the more accurate you learn to judge it
dp