I have to admit, I've never been a fan of the dope and balsa dust trick as a filler. The main reason being that the balsa dust I collect is probably crap.
The place where it collects in enough quantity to make this worthwhile is around my old drememl scroll saw. It's not an ideal medium as it's full of ply dust, sometimes maple dust and carbon fibre dust and whatever else I've been using the sanding wheel for.
It usually ends up and inconsistent glob, which doesn't sand the same as the rest of the model.
Like most of the guys on here, I prefer not to fill, by taking care of the model with pillows, and blankets on the workebench after I've started to final shape. Inevitably you'll get some dings, and if you're like me (a spaz) you'll make more than your fair share. Some can be removed with a simple lick, others will get the water and iron treatment. I still ahve to try that vinegar technique though!
The only thing that gets filler on my planes is fillets. The rest is generally made from balsa. (even fillets sometimes!)