I have used Expanders from the start, and I would say they help overall. However, as time has gone by I have discovered better ways of putting them together, so I have ended up changing many I had already created along with the endless making of new ones. (Some of this due to discovering which key combos are easier for me in regard to finger dexterity and some due to overlapping use of the Expander pattern I started with.)
I think you might actually be better off since you have learned more about transcribing before creating any.
I did read a funny and interesting thing on here a few months ago though. Someone said they stopped using their expanders and were getting a higher line count by straight typing. I was really tempted to try it for a day to see what would happen but never did. It would be kind of fun if we all tried it for a day (or even half a shift) to see the range of results.