I am a big fan of Brillianize for use as a ball cleaner. Whatever you do, don't use anything that adds a layer, a film, or a wax. Novus may be a good product as well. It seems along the same lines as Brillianize.
*edit* To answer your 2nd question... I don't think the tip will ever matter as far as chalk transfer to the cue ball. Well, maybe, just maybe, a super soft tip would transfer a miniscule amount more than a super hard tip just due to the amount the tip flexes on impact, but I am just guessing. I think, regarding this question, what matters more is the chalk used. I think you will find that Kamui chalk will transfer to the cue ball more than most others. I feel this has to do with the clingy nature and "lipstick" feel of this chalk. (Although I have no idea how many guys on this forum know about how lipstick feels when you are putting it on, but that's another story.)