Agreed that you can do whatever you like, but to me, a Wee Heavy should be a big beer with a thick mouthfeel and lots of residual sweetness; using sugar to get your extra gravity points won't give you that, it will thin out the body and dry the beer when compared to using malt to get those gravity points in there. Have you considered using some malt extract instead?
To be honest I never even thought about using dry malt extract. I was afraid corn sugar would dry it out. I'm going to look into the dry malt extract to offset me over cramming the mash tun with grain. Thanks for all the info.