I can't speak for the silk powder but I use the Ultimate Luxury Treatment Powder without tinting and it doesn't look chalky at all, just provides a nice softening effect. My favorite thing for no makeup days is actually Date Bait. I know a lot of ladies use half and half ratio Date Bait mixed with their favorite sheer or white powders instead of foundation. You could always order a small sample of each (and maybe the Zinc powder too?) and try them out.
Thanks! I'll try samples of all 3, and wait to start tinting and mixing until I figure out my foundation.