[SG, figs] vehicle resin putty question

G'day guys,

I' picked up a Paladin (the big wheeled tank) from Nic a while back and
will be trying to put it together in the next few months. A quick look
makes it pretty clear there is a sizeable gap between the two halves to
fill. Derek does have some putty ideas to try from his model building
days, but I thought I'd just double check to see if anyone with more
recent experience had any advice on the best stuff to use.

Thanks

Beth