Hi @robbinsmith, in the case that the post is not older than 6 days and was not commented by cheetah, boomerang will vote the post depending on how much buds we received for other posts. If the post is not voteable, boomerang will automatically send a refund.
For example, if you bid 0.05 SBD, and the sum of all other bids is 0.95 SBD, boomerang would vote your post with 5%. Usually the sum of all bids is currently in the range between 5 SBD and 15 SBD, in this case the vote for the 0.05 SBD bid will only be 1% till 0.3%.
To get realtime information about the current amount of bids and the time till the next voteing-round check these awesome webpage.
https://s3.amazonaws.com/yabapmatt/bottracker/bottracker.html#bid
and read this post
https://steemit.com/adsactly/@adsactly/adsactly-on-steem-tools-iii-steem-bot-tracker
To your second question. There is no maximum amount for the bid, but please consider that the value of the 100% vote of boomerang is limited (currently around 20 US-Dollar). Just check the tool above to see of bidding for a vote is profitable or not.