SO the shellac I ordered from Amazon has fixed the tackiness on all the minis I have used it on, and gives them a great shiny finish - I know a lot of people out there love matte finish, so for those people you may need something else. But it has rescued a number of minis that would otherwise have been lost forever - i.e. so tacky they were sticking to other minis and losing chunks of paint.
Going forward - I got Army painter primer for my reaper bones - and it worked great - no tackiness at all - so I recommend that. Also it is on the Dwarven Forge game tiles recommended primer list.