Assuming the Germans had used them according to your post, the Zeros would have been quite formidable in German hands, for a while, and might even have turned the battle. The British pilots would have taken a while to change their tactics to meet the smaller, and more nimble zero that was now escorting the German bombers all the way to the targets and back, and with plenty of fuel left over for lots of dogfighting.

The japanese guy you cite has a good point since the main, possibly decisive, disadvantage of the Me-109 in the Battle of Britain was its short range; and the Zero had a very long range (1,000 miles). The Me-109 carried only 75 gallons of fuel (in the tank behind the pilot). In 1940 nobody had thought to fit drop tanks to their fighters, those came alot later.

This oversight probably cost the Luftwaffe the Battle of Britain since no decent fighters could accompany the German bombers, only the clumsy and unmaneuverable twin engine Me-110, which was meat on the table even for a Hurricane.