My appliance is 62% and deco is 42%, upgrades on food is between 90% - 100%. My combo is Fast Feet and Rush Hour and I don't have a problem beating Gordan.
Nope, once you lose your opponents score does go up but I've noticed if you keep at it, it will eventually go down but then start to climb again if you lose. The money you spend on upgrades will stay when those items roll back around, so let's say you upgrade the veal fully and next week it's not there but the following…
I have all 5 wishelin stars for PP, I've had it for about a couple months and I've gotten prep dishes about twice. Honestly it isn't worth it in the amount of gold you end up spending.