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25mm tyre (made bigger by the wide rim? 27mm?) will fit a SuperSix Evo frame?
More likely to fit with wide rims than otherwise, as the limit on the SS-Evo (and other bikes) tends to be with the tyre height behind the RD clamp and/or under the fork crown. Widening the tyre on a big rim tends to lower the height. People fit 28s to SS-Evos, so 25s should be fine for both width and height.
You don't need posh rims. Kinlins are fine.
DA hubs are very nice and with them comes the option of using your favourite builder. 28 / 32 spokes will be easier to keep true and functionaly even tension than lower counts.
I'd probably save cx-rays for 'fast' wheels.