At 85kg (187lbs) you could handle a little more foam but thats kind of personal preference.
Does the twinsman feel like a good size for you? If so I would probably shoot for a similar volume.
Im similar weight to you but tall (6'3") and surf mostly in a 5/4 hooded. My twinsman was a stock 5-10 and my Bomdia is a custom narrower/thicker 6-1 x 19.25 x 2.6 33L.
I prefer the Bomdia in just about every way. Rode mine a ton on my recent trip in all sorts of waves. Here's a shot from my last session on a fun sized day.
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