The reason to run perpendicular is for the joist to bear the load. Is it
over kill? Wait until you unload 300 sq.feet of 3/4" flooring and get a
real feel for what is going to weight! We actually stacked some of our wood
flooring boxes PARALLEL to the joists (like your proposed installation) and
the plywood underfloor bowed and flexed! We re stacked perpendicular.
Overkill- no. Architecturally correct- yes.

--
KB

"Eric Johnson" wrote in message
...
Rule of thumb I was taught is it takes an 1 1/2 inch subfloor to keep
ceramic tile from turning into dust, that said I think that even if you
add
the subfloor to build up to 1 1/4 I'm betting the floor would have some
waves in it after some time. Maybe if you had access to the joists
underneath you could add some solid blocking?

EJ