Sorry to be a pain Cheesy as you reckon you have chosen a SUP but I reckon you will outgrow a 10ft Mana very fast - it is a BIG board! 33 wide and 190 litres volume is a hell of a lot for someone who has surfed all their life....reckon you will want a bit more feeling/challenge from a board. Can't help thinking you are going to be selling this sooner than you think....got to be other boards out there that are better all rounders which are not so big.
Just my opinion of course....if you can demo then that is the best thing to do...save you cash!
And as for those few words about you nearing 40 so need to be SUP boarding......being on a SUP doesn't mean you are past it