Ok, I do a fair amount of this so, here is the advice.
'Scrabble it!'
What I mean is, yes, by all means have a long stitch length, but as you feed the tulle under the presser foot, push more fabric in as you go. Go at it quite fast, as well, and just keep pushing it in.
The result you get, as a sewing perfectionist, will look rubbish, but when it is pinned onto the mount- yokeor base- it will come together and no-one will know!
This is much the quickest way to do it, but you do have to watch out for the edge of the tulle veering off sideways, and not following the line you want
I was taught this by a lady who did a lot of costume making, on a semi professional basis.