Idea
by GulaManYOWSponsor gets 5% of the auction if the Art he/she sponsored wins the Art Race. This is to reward everyone who contribute.
Discussion
I'd personally prefer keep at 0.25% so that large majority goes to the artist. Sponsoring should be because you like the art/want to see everyone have a chance at entering the collection imo
Sponsor gets 0.25%
Maybe lower that 5%, or increase the reward by 5% (total 25% proceed, 20 for artist, 5 for sponsor)