Engine on P&G it think is tough to do and make a large gain in mpg vs just driving the average speed, unless you have so hills to help extend glides.
http://ecomodder.com/forum/showthrea...oad-19594.html
Check out post #8, it shows how much the engine load during the pulse can affect the efficiency of P&G. Later I asked about his constant 32 mpg and he said it was 51-52 mpg in 4th, 55 in 5th, so pulsing at 70% load was only netting him up to 4 mpg and he was going engine off.
Since your thinking about going back to the 14" for winters, Nokian makes a WRG3 directional in 185-65-14 so a little taller than your OEM 14" $72 at simple tires not quite as pricey but I believe is still LRR.