it is commonly called canting on boots though.
to adjust the canting properly you need to see a bootfitter, you probably just fucked up your boots and now they definitely arent going to be right so i would take them back to where you bought them to get them adjusted.
what boots are they? what is your forward lean angle? most people rock around a 14 since that is a pretty stock lean. 12 is as straight up as you can get i think, anymore then that and you will probably be falling over backwards. more agressive stances are around 16-18.
i will respond with what i say in every forward lean thread, i hope onenerdykid replies also as his response his more on the technical ends of things.
so here goes, forward lean is something that is personal, some people like a more aggressive stance and really preload your tips, this is what i prefer, and some prefer the straighter stance. if you think a straighter stance will make it easier to balance on rails that is incorrect.
it also has alot to do with how your ankle flexes and making sure everything lines up, this is why a bootfitter is recommended, however my opinion is still that it comes down to trial and error and you need to find what works for you best.