Just a thought from my own personal experience.
I never had luck with the mixing it up thing; the throw one thing on field work and something different during rounds. I just found it frustrating. Muscle memory is a funny thing, and as soon as I put the heavy regular round disc in my hand, the regular heavy round disc throw was back. It may work for some, just didn't work for me.
My watershed moment came when I met up with one of our local pros on the first tee. I had my normal bag and he showed up with a 160gr dx Skeeter. He had developed a small timing issue he was trying to work out and was there just to play a one disc round, (by the way, he can throw mids 400ft). So we played a round, and yes, he totally kicked my a$$! On that day, I changed my game and my outlook.
I followed the "how to build a bag thread" advice. I put together a bag with a DX Aviar P&A, DX Roc, DX Cheetah and a DX Eagle, all 160 grams. Wasn't even a bag really, most times I just carried them in my hand. And that was all I played rounds with. I was teased, made fun of and riddled with all the usual question that those who never tried it assume you won't be able to do. What are you going to do in the wind? How are you going to throw this or that shot with out X,Y,or Z disc? You need a Firebird and an approach disc! Just a lot of gibberish that has become ingrained by manufacturers in the bag videos.
When you have limited amount of discs, you learn how to throw them on many angles and in many conditions. It's a real eye opener. I learned to slow down and become a smooth thrower. By the way, this little experiment boosted me leaps and bounds in the forehand game too. When you learn how to flick a light weight DX Aviar, you can flick anything. Discs don't have limitations, people do. People also lack imagination.
I don't know, maybe some can do the practice one way and play another, it just didn't work for me, besides, I was always told to play how you practice to ingrain what you have been practicing.
I also think it's an ego testosterone thing. I see it all the time when I have played with newer players. You take the time to teach them, and the next time you see them out with their buddies hucking Destroyers on 250ft holes. Group mentality never likes a trend bucker and it can be hard to be the odd man out. But do you want to be better, or do you just want to fit in?
I think it's far more satisfying parking a 250ft hole with an Aviar, but that's just me. I think it takes a bit of courage to find and play your own game, but in the end it has been rewarding to me and that is what I try to teach newer players. Pay no attention to the torque monkey on the next tee, in short order you'll be throwing a controlled stand still midrange the same distance!