Foe me it was the Tyros 2.
I have added the NP30 as lower board Twinset style
I saw a photo of your twin setup on PSR Tutorial, Graham...it looks very good, indeed, just like they were designed to be that way. The NP-30 has a very nice semi-weighted action.
I have passed on your idea to several friends of mine wanting a two manual setup.
Do you use bass pedals as well?
Ian