If its a "stock" short tailed C/G VooDoo circa early 60's, then it was designed when .015x60' were used and the leadout sweep might be a tad on the light side for .018's which became mandated in the late 60's or early 70's.

I recently built a short tail VooDoo from plans and moved the front leadout back 1/2". For .018 flying this turned out to be about perfect, and corresponds roughly to what Goldberg was recommending in their later kits with a little paper addendum insert in the long tail VooDoo (which appeared somewhat after the .018 requirement)

A good C-35 is powerful enough to keep it out on the end of .018's even with the original early 60's setup though. Its just not going to pull as stoutly.

I put a ST .46 in mine fitted with the wide open G21 pressure venturi spinning a 9x8. It was pretty fast.