I not comparing cheap Chinese tubular rims or carbon clinchers, but I am comparing the performance gains of a quality carbon tubular wheel versus mavics high end clincher wheelset when there is only 50g difference in weight.
and I answered in a very generic way given the broad assumptions you made
Lets try and answer the simple question is the Mavic R SYS CL clincher a better wheelset for you than a Vision TriMax Carbon TC24 tubular
Tyre choice, your choice of which clincher + which tube or which tubular tyre is going to affect overall wheel weight, either amplifying or negating the difference between wheels. As well as making a bigger impact on ride quality that wheel choice.
Assuming tyres do not impact on the weight. A better physicist than me will tell you 50gm saving in weight will save you X watts climbing 1km at 10% under laboratory conditions which translated to you arriving at the top of Alp D'Huez Y seconds faster with Vision TriMax Carbon TC24 wheels over the Mavic R SYS CL. I would say X and Y are small numbers.
Punctures, going uphill I rather be on clinchers, easier to repair, going downhill I rather be on tubulars more control of bike with a flat.
Braking, do you find you are constantly on the brakes going downhill, because
a: you are a nervous descender
b that is the way you ride and the roads you ride
c in sportives the others are poor descenders
d you ride in big bunches
If you answers yes to any of them then get the Mavics. Though if it was A consider a good pair of alloy tubulars
Do you ride like a lunatic in the rain?
Get the Mavics, better braking in rain on alloys I am told.
Convenience the Mavics are easier to change tubes and tires on, the Visions easier to get a replacement spokes for.
There is no reason why you should not get the Mavics, as they do what you want, though if your budget can stretch to some Zipp 303 Firecrest Tubulars, just as fast uphill as the Mavics and much faster down the other side