The Hyperlite Motive is a great board, I have one we use as our boat board. The 134 sounds like it would be perfect for you, but I'd maybe go with a little bit better binding than the Vario. I have a pair of 04 Vario's on our old boat board I got as leftovers from my dealer and nobody likes them. When I got our Motive this year to replace our old boat board I got a pair of '05 State bindings with it. In all honesty, the State is the cheapest Hyperlite boot I'd consider buying. The boots are more important than the board. Hyperlites lower line boots don't offer near the support that the States and other boots do (overlay material isn't as good).
As far as your dad and you using the same board, if he weighs 180 he should probaly be on at least a 138. Hope this helps