Hi I’m baking the wedding cake for my grandson in Nov. I’m doing a 10”,8”,6” what I want to know is should I do two layers or should I do three layers of each size? I thought about torte them but thought it might be better to just add an additional layer to at least the 10”& 8” ones. Any thoughts ? Serving appx 100 or so people . Want it to look substantial and beautiful. 

I think this is really a personal preference.  I prefer the look/height of a 3 layered cake over a 2 layered cake but by adding a third layer you really aren't creating more servings, just taller slices of cake.  Your current plan for a 10, 8 and 6 you will only get about 75 servings and that is if you are cutting it "correctly" meaning you are cutting it how a caterer would and not a random joe slicing up a birthday cake (aka slightly more generous servings).  You could do a 2-layered 10", a double barrel 8", and a 2-layered 6".  This would get you to 100 servings and also possibly provide you with that substantial look you are looking for without having to add an extra layer to each tier.

For me I like to stack baking pans or dummie cakes to see the approximate final size so I know that I will be happy with the end product.

Thanks for your quick  reply I plan on making an extra cake that the caterers would cut in the kitchen so would have more than enough servings. I think I'll do the 3 layers of the 10 and 8 inch cakes