Depends I suppose - do you find you catch loads of waves on the FB Flyer? Do you sometimes feel like its too much board when up and riding want something more responsive? What kind of waves do you find yourself out in mostly?
To be honest the Dwarts are quite performancey boards compared to a lot of today's super grovellers, they have quite a narrow nose/tail and are quite foiled in those areas which is good for when the waves have more juice but not so good when they have less power, fatter etc... I weigh 70kg and had a 5'8 Dwart copy for a while, intended for any shape waist-shoulder high wave type days;
It paddled ok and caught almost as many waves as my 5'10 Speed Dialer fish but I wouldn't say it 'got you into waves easy' and it was responsive to the point of being twitchy (for me) when up and riding, more twitchy than the 6'3 high performance shortboard at the time. Overall I just couldn't get a rhythm going with it and shipped it on. Maybe mine was too small or maybe I just didn't suit the shape. So i'd say if you do go for one at your weight don't go too small, you'll probably hate it, if you're a pretty confident surfer go about 6'2 at the smallest to begin with - ideally find a surf shop that'll demo a board out to you or buy second hand to minimalise the loss if you don't get on with it.
If you like the shortboardy type surfing but want to cut length you're probably better off on a Fourth Doofer or Bumblebart in around 6'4 - http://store.magicseaweed.com/product.p ... ctId=55910
Don't go too short too soon I reckon as you'll only regret it (I did)