Never actually tried this myself, so take my advice with a grain of salt: if you're not sure what ratio is best for you, find a vendor that offers cheap samples and the option to customize ratio. Then order one flavor you like in all available ratios. Shouldn't break the bank, and you can get a better feel of your reaction to each, while keeping the flavor a constant.
Personally, I haven't had issues with pg or vg - though vg does give me more cotton mouth/throat than pg. I'm still playing with flavors and ratios myself, trying to find what I like before fine-tuning the diluent ratios, but maybe the above suggestion can help you out.