Hi Airhead,
that's my 138 x 41 freeride(foam core twin concave) light wind wave board in my avatar. Love the board. I'm also 75kg. Only use surfboard in xtra light wind(6'7"). Like you I was impressed by reviews of Tempo. I bought a 137 x 41 quad concave Tempo, thinking to upgrade the freeride. - NO GO - Freeride gets going & upwind significantly earlier. But with that bit xtra wind Tempo is very exciting to sail. So I've got 2 light wind boards & luv both.
You're not starting out, got enough wind, whether slashing waves or doing tricks it's a no brainer for you, go the Tempo.

cheers
COL