I've done some work with Slosh Pipes before - the only thing I'd say about your slosh can is that there is little potential for the water to move around (i.e. it is contained in a relatively compact area) and this is what made the slosh pipe so tough. It will undoubtedly be more challenging (for the same weight) as a regular free weight though.
Have you tried doing a bottom-up press with your slosh can?
I like the blog and it reads well.