if we request 0.05 or 0.1 SBD per month or $0.1 upvote per month, that will cover server costs for now.

This is a great idea. If I may suggest, use this @steemauto account to post daily stat, users then can vote daily and help cover the cost. It's better to give daily stat so that small minnows could still give enough to steemauto. If you only have one monthly post, the smaller minnows could not afford the upvote value.

Also, as a reference, you can copy Qurator's way of upvoting:
https://steemit.com/qurator/@qurator/qurator-tier-changes

P.S. Of course, I vote you as a witness. :D