I gave up after my 3rd longboard front flap snapped off (the first two took part of the guard off too). I ended up buying raw flaps which are lighter and seem less prone to breaking the mudguard. Bonus is they're reflective and longer/wider.
They do look good. I'll save buying them for when the replacement falls off. The only reason I haven't gone straight to them is because the flap on my Pompino sits lower than the road bike and it's still firmly intact... that might be the exception rather than the rule though.
Can you buy and replace the plastic flap on Longboards? I appear to have lost the front flap on my road bike.