if you use heavier strings the action will be higher without having to do anything else to your guitar. I find I can go as high as 13s before bends get away from me. I don't think there is a right or wrong way for
slide hand position. If it works and isn't hurting your hand then it's right for you. When you get a dropped D slide, your slide hand positioning will return closer to your normal non slide hand position due to its' shorter length and not having to damp behind the slide as thoroughly. Just my opinion.
allthumbs