Hey Bob,
Yesturday I looked at the saito engine specs.65`s are actually heavier than the Saito`s 72`s.The Saito is a very light engine at only 470 grams.I have 2 x SAITO 40`S in my Jack Stafford Twin Commanche,nice and light at only 290grams! I think it is so important to keep engine weight down to a minimum on twins whilst still retaining sufficient power reserves.
Also maybe a consideration is the OS 70 Ultimate which is also around the same weight as the Saito 72 but also more compact than the Saito or OS 70.
Steve