There was a thread a couple of months ago regarding filler, can't find the thread now but...Red Devil One Time was recommended, so I got some off t'internet.
I finally used it on my Dynam Spit rebuild last night. Top recommendation, this stuff is superb. So light it feels like the tub is empty. It has the consistency of mousse, spreads so easy, if you use it carefully you really do not need to sand! I don't need any more just at the moment, but I am going to get some anyway, best filler I have ever used.
By the way 'Bounce' filler got a good review in the mag, so I bought a tub.....and threw it away after 4 or 5 totally failed attempts to repair a dink in a foam wing, the stuff just fell off, sorry but I was as unimpressed as you can get!
Give Red Devil a try.