I need your thoughts and experience on potty training.

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Some background...
Now that my sweet boy is quite the swimmer and I am not going to lessons EVERY morning for 8 weeks (8 weeks?!) and a baby due in 9 weeks... we're in the throws of real, official, potty training. As I mentioned in this post -- he has been pretty consistently going poo on the potty since 18 months. It's the pee we needed to work on.
Sooo... starting Monday we began officially. I had him either naked or in loose undies and each time he'd start to pee, he'd look up and say "go potty!" with a surprised look, would stop going and would finish peeing in the potty. That's pretty much been how it's going for 2 days. Wet a little, finish in the potty. After he goes I tell him he's a big boy and do a silly song with a dance. (Thank goodness you people can't see that on camera!) He laughs and that's his "reward" for using the potty.
Thank goodness we have hardwood floors everywhere, so cleanup has been easy! : ) And we still do diapers for naps and bedtime.
My questions for you:
Is that normal that he starts going a little before he realizes it and finishes on the potty?
At 23 months old, how much should I "help" him go potty? Right now I go in with him and help him pull down/up his pants. He doesn't ever really go in on his own-- he always tells me he needs to go and we go together.
Did your boys sit or stand to pee?
When did you venture out in undies and know they'd tell you if they had to go?
We alternate between his little potty or the seat on the big potty. What's your preference for your kiddos?
Any thoughts and advice are welcome... I admit I did not read any books on this and have been winging it and feel like we're getting somewhere but I'm not sure.
