I’m trying to get to Dribble for about 3 years, but was not able to get invite yet
Actually this is not a secret, because sales and prices are publicly visible and you can easily estimate commission rate. Take a look at http://tf.marketopia.net/popular_item/by_category which makes all those calculations from public data – you can see total earnings, last 30 days earnings, average monthly income from item etc.
As Demorfoza said – there’s no easy workaround for that. You need to change canvas size and then manually adjust the content to make everything aligned just right.
Quality, quality, quality.