Would need to know which Diamana that is: blue, white, red etc. The Tensei line has taken over for Diamana for the most part for Mitsubishi, with the colors pretty much matching up between the 2. The stock shaft on the TSR4 is the Tensei 1k Black which is a similar profile to the White shafts in that they are both low launch, low spin, high kick point. I have the TSR4 10 deg in that 1K Black and love it. If you love your current shaft, perhaps try to match up what would be the most similar (and you can also use that same shaft if you want, they are interchangeable).

Which Diamana - and what issues are you having? TSR4 is the lowest spinning head so knowing your current launch conditions (launch angle, swing speed, spin) would be helpful in suggesting a shaft.

Metropolitan Golf Links is having a fitting on this date. See you live in San Fran.

Tue Jan 24th
10am-3pm
12.9 mi
TITLEIST FITTING DAY WITH ROBERT OROURKE AT METROPOLITAN GOLF LINKS
10051 Doolittle Dr Oakland, CA 94603-1025
Directions (510) 569-5555

The Tensei Black 60 S is a Mitsubishi stock option, should be comparable