I definitely would not self-vote at all honestly. I rarely do anyway on my posts, never have on any of my comments. I consider myself an extremely active user and I spend a lot of time on the site just reading through everyone's posts that I am following as well as reading new posts in the "new" section.
I comment whenever I can think of something insightful to add to conversation, or if I can leave a genuine compliment for the person's work. Having that SP delegated to me would actually allow me to space out my percentages more to start giving more worthwhile upvotes that I wish I could give more often!