Yes, it's 'acceptable' to meet with another notary, but you can't tag along on a signing due to privacy issues. However, fairly certain you'll have some difficulty getting an experienced signing agent in your area willing to 'train the competition'--you!
There are quite a few Youtube videos of 'how to do this' (in every one of which I find some nitpicky flaw or another), but they will still give you quite a few tips on the process. Tho' I've never seen one with a 'difficult' signer, I also know that every single one I've had has been difficult in a different way and you have to figure it out on the fly.
This is one of few jobs where you learn as you earn. Get your feet wet..