I'm sure you already have enough to work on, but I wanna make sure to introduce you to the approach that made me really start to get it.
Ultimately a scale is just a bunch of notes, and it can seem easy to just learn the melodic minor scale and then apply it in different ways- For example up a fifth for the lydian dominant sound and up a half step for the altered sound.
But in this approach I personally ended up giving up on learning the melodic minor scale, because it didn't make any sense to me. Because even if I played the scale right, I didn't really understand what I was doing!
So I then learned the notes and their qualities one at the time, and eventually they formed a scale. So try this approach:
The main uses of the melodic minor scale are as the altered scale, the lydian dominant and as a minor scale with a major 7 and major 6, so we'll start with that.
[U]Playing melodic minor over a regular minor progression:[/U]
The first note you wanna get comfortable with is the major 7 over a minor chord. It can sound pretty retro and cool, so try to play some phrases that incorporate the major 7 (fx b3, maj7, 9, 8) Once you get used to this sound you can easily add the major 6 (fx 5, maj6, maj7, 8 and so on...)
[U]Getting comfortable with the lydian dominant sound:[/U] Try and play some phrases in the mixolydian scale using the #4 instead of the regular 4 (for example 5, #4, 6, 5, 3 and so on). Get comfortable with that sound. That's all there is to it. Once you understand the lydian dominant sound it's much easier to find more places on the neck where you can play it.
[U]Now try the altered scale:[/U] Try to play some phrases that incorporate the b9 (fx 1 3 5 b7 b9 8)
Once you get comfortable with this sound, you can add the b3 to the mix and find some cool phrases with the two tension notes.
Then you add the #5 and find some cool phrases with the three tension notes.
Same thing with the sharp #4, and the rest of the notes you already know! The 1, 3 and b7
All the other modes of the melodic minor scale are very advanced harmonically, and I wouldn't worry about them till you wanna try to sound like Coltrane!
Hope this helps and didn't confuse you. My main point is that rather than trying to learn all the notes all over the neck, just try to learn to understand the sound of the most important ones, and eventually you'll know the scale just from doing that. That's how I did it:)
Have fun with it and feel free to ask me if anything was unclear,
Anders