Are you really sure you want to do this? For a room as small as an average
bathroom, put in some new tile and it won't be that much more expensive.
And a tile floor is SO much nicer than that vinyl junk.

You won't have to worry about your height difference and you'll have a MUCH
nicer finished room (assuming you do good work) than if you put down vinyl,
which just screams 'cheap' to me.

-Tim