I think it depends entirely on the dog!
I run 3 show type cockers and all run differently, Paisley will NOT run ahead of me and so it's nearly impossible to cross behind her unless it's contact kit. She refuses to do 12 weaves and I wouldn't trust her doing right hand weaves, not even 6! And she's been doing agility for 3 years now!
Isla my deaf girl, she stays close enough to me to keep an eye on my body language for directional control and amazingly does brilliant cross behinds and goes the right way after the jumps 9 times out of ten, she's now brilliant at weaves and I know she will go in and stay in for all 12! (just need to work a little bit on right hand weaves with 12 but she gets her entry really well now!)
Neither of the girls have ever been very sniffy so I never have a problem with them wandering off.....only if they're really tired and have basically given up for the day!
Obviously with them sticking my me they only really run as fast as I can go and sometimes I find myself waiting for Paisley!
Merfyn is my youngest and so a bit of a live wire, with him being a boy his nose often takes him off to sniff and pee on things, I'm hoping as he gains focus on what he's doing he'll grow out of this. He's only 16 months so not sure how he will be weave wise but he seems to be progressing quicker than my girls did but that could be my more experience now as a handler! He is confident with all kit and is more than happy to run ahead and boy is he fast! Because he's so fast he is prone to going wide on tight turns and therefore getting us eliminated but he is very young so that's one of the things I'll be working on with him during the winter!
I find I also have to be more high pitched with him to keep his focus and have to keep commands and praise flowing to keep him interested whereas the girls just get on with it with little vocal commands from me at all! (obviously none with isla!) But this is probably because he's still so young!
Perhaps there is a difference between running girls and boys generally?!