BG 44K Fuel System Cleaner Power Enhancer with Funnel

can I use 44k every 3 months or it's once a year

I have a 16 gallon tank in my 2012 4 cylinder chrusler 200, could i just use the whole can for my 16 gal tank?

my cars tank is only 12 gallons, can i still use the entire can of cleaner or do I have to use 3/4's of it?

I have a 2006 volkswagen passat vr6 (fsi) would recommend this product? thank you