I've heard there were some studies in France showing that PG produces formaldehyde when vaped, not sure if this is true, but in my opion straight VG is a better choice for safety and health. As for vaping in general, I am curious to try a 70 percent VG and 30 percent distilled water combo.
A blend of 70/30, 50/50, 30/70 will prob do just fine without having any issues.
A lot of sugary stuff and syrupy stuff is going to clog your wick more so than the base solution.