However I noticed a while ago that I was getting a lot of bleed in my vocals using headphones - could be that I use Sennheiser HD480 that are not closed back.
That'll be it. Also a lot of vocalists like a helluva monitoring level or even only hold one headphone to their ear and leave the other loose - which is a product of the music video generation, 'cause they've seen some or other star "recording" in a video and
they
do it that way (so it must be right). If a singer wants one ear free, I try and get them to slide the one phone back, so it is still sealed against the head.
The greater advantage to this recording technique is that my vocalists were a) more relaxed, b) listened harder to the backtrack and were able to pitch better, generally a better performance from my artist.
That's mostly due to the fact that you are limited in monitor levels. You'd be able to do the same by keeping monitor levels low in phones too. It's a fact that the best cure for a vocalist who either pitches sharp or pushes too hard is to turn down the level in the cans. They listen better and they hear themselves clearer.
Here's a trick to try if you like using monitor speakers for tracking monitors: plug in a second mic, preferably same make/model as your vocal mic and position it anywhere from 3 to six foot from the singer, but at approximately the same distance from the monitor speakers. Set input trim, EQ and levels the same on both too. Then flip the phase on the second mic channel. The two pick up similar things from the monitor speakers, but only the main mic picks up the vocals. When they sum at the console, the out-of-phase signal from the second mic cancel most of the leakage, but leave the voice intact.
Actually the same thing works for live sound with two vocalists at the front of the stage - flip the phase of one, and all the sound that both hear (the leakage from everything else on stage) cancels, but the vocals are left intact.
I wouldnt call my recording red book standard but they are pretty damn good for demo purposes and especially for capturing the idea before it fades.
I've no problem with that at all, and the clip of yours I've heard bears out you are getting good results, but if you can improve them even more with little to no effort or expense, why not?