I think you should stay with the same bit too, if its what he is used to. It sounds like he was just being snotty that day. I always keep a rope halter on my horse while trail riding and tie a lead rope to my saddle. If you don't have someplace to tie one, put snaps on the end of your reins so you can unsnap the reins and snap them to the halter. That's the first thing I do when I buy new reins is attach snaps to them. They make a great emergency lead rope that way. I have had horses that I had to do an attitude check with before mounting up its good advice and will save broken bones in the long run. Just doing a little yielding of the hind quarters backing up etc. for a few min. Before getting on. This is also a good time to check your tack to make sure everything is riding ok and not hurting the horse. Do some lateral flexing for a few min. Too after you get on to get them giving to the bit . I'm not a big fan of lungeing I think it just wears them out.
I too ride a mountain horse and its diffucult to ride with non gaited horses somtimes because they are a little slower. When I ride with our club I have to break away from the croud every once in awhile to let Vida do her stuff. I also ride with friends who have Peruvians and its a lot more fun
I don't have to keep slowing her down because her "walk" is faster than a non gaiter. We ride at least 20 miles a week on our own and when we are riding with the group its tough for her to understand why she has to baby step.
I also have worked on her understanding the word "easy" it means slow down to her. I say easy and give a slight pull on the reins when she slows I release the reins and say "good girl". When I first got her she knew no voice commands not even whoa. She has come a long way in the 3 years I have had her.
I want to add that I ride Vida in an Imus bit and we both love it. If you decide to go to a shanked bit I would suggest this one. Its made for gaited horses. http://www.gaitsofgold.net/
It has really helped Vida collect up better.