I'm not sure about the resin and talc method, but I do know about the clear dope and talc method. If your looking for the non-baby butt talc, try your local pool table suppliers. Talc the sell is reported to be great for this non pool hobby use. As for myself I've been using clear dope and common run of the "mill" corn starch as you find in the kitchen to do a similar service. Again, not sure how corn starch reacts with resin materials, but it is inert in dope as a filler medium. If the starch content can be kept high and in suspension, it sure do sand easy when the dope is dry.

Tony