It's actually easier for minnow upvotes to get a high curation reward ratio. By this I mean as a minnow you can easily receive 100% of your upvote value as a curation reward. This is much harder for a dolphin or whale to achieve. The mechanics work on larger rewards if a relatively larger volume of upvote value follows your upvote.

However if you have a 1c upvote then a 100% ratio is a 1c curation reward. Whereas for someone with a $1 upvote a 100% ratio woud be a $1 curation reward. So in general it's not worth minnows focusing too much on curation rewards, but on posting, commenting, interacting etc.