this project on Make and realizing that I use that exact same shampoo, I thought I'd give it a try.
It turned out pretty well. I decided to make my pocket deeper than the one on Make. However, I'll probably end up cutting it shallower because it's difficult to pull the phone out. As is, there's not enough clearance between the top of the phone and the plug without allowing for more angle when pulling it out.
Another thing I did was use masking tape to layout the cuts instead of a marker. That worked quite well giving me nice straight lines and making it easy to revise my design several times before doing any cutting.
Since I needed a European version, I couldn't use the provided template for the plug. Instead, I again used some masking tape to layout a square hole. First, I applied the tape in a square on the plug itself. Then I peeled it off carefully, stuck it on the pocket, and cut it out with a razor. It's a perfect fit.
Cutting it about an inch deeper and making the hole in the bottom larger made the pocket significantly more usable.