You might have already considered it, but as a potential user I'd like to have the chance of adjusting the percentages at each billing period (month for example) to avoid rewarding sites that use tricks to increase page count or other metrics.

By default, percentages go to each visited site as determined automatically by your service.

I'd also like to veto certain publishers, to avoid giving them money when landing there from obscured redirections or by accident.

Of course, if I veto a site then I would not get privileged access to it. That's fine.

That might be at odds with your three-party verification scheme; this is just a suggestion in case it might be useful.