When I have hemmed tissue Lame or liquid Lame I have used a piece of ribbon on the bottom and done a picot or rolled hem edge. If you don't use some sort of stabilizer then the fabric distorts. Such as pulling, puckering, gathering or shredding.
I can't remember the exact name of the ribbon but it is sold in the bias tape section. And if I still had problems then I used a water soluble stabilizer on the top and just removed the excess when done.
When serging the seams I adjusted the differential feed to a slightly lesser number (on my serger between 1 and 0.5) and lengthened the stitch so it wouldn't gather. As always test on scrap of same fabric FIRST!
Believe it or not I made pajamas and nightgowns out of the liquid Lame for the kids. They just loved it - thinking they were super heroes. It was fun.