I know the feeling Luka-pop, I am not a very stylish rider myself!! I ride like a duck - toes out, and only last year I noticed that I ride with my arms completely straight - not bent at the elbows!! However I get the "job done" and my horse responds nicely to me (probably used to my "style" after 8 years!).

Lunge lessons may help you learn to ride more from your seat and rely less on your hands because the horses head will be controlled by your instructor on the ground.

I hack Ross out in a pelham with double reins (in the school he has a loose ring french link). I use the double reins because that way the curb only comes into play if I need it and the horse is not being constantly "punished". I keep both my reins even and as the snaffle rein goes outside your little finger when I ask him to slow down by squeezing the reins the snaffle is pulled more than the curb. If he gets excited I shorten both reins and the curb comes into play more. The curb should have little ill effect - tightening of the curb chain on the jaw or effect on the poll - on the horse if fitted correctly unless it is specifically used when it is needed.

Here is a good site about using double reins:
http://leeziegler.com/pelham.html
This explains that there are many ways to use them and you may use them a different way to myself (British style with the snaffle rein below the curb).