I'm trying P&G with my LW 200 and I'm finding that this car responds well. I have been doing the +5 and glide to -5 of the limit. What I'm seeing on my scan gauge is astonishing this tank will be my best EVER 32.7 mpg and it may end up higher. I'll log results in my gaslog so everyone can see how it worked or didn't work.
my plan was not actually to exceed the limit by 15 but rather have a 15mph window for the P&G to occur instead of the 10mph I have been using.
Ah, that's +/-7.5 (or maybe +5/-10), not +/-15 (which would be a 30MPH window). I'm thinking +/-15 would not be a tolerable way to drive, either for you or for the other people on the road. +/-7.5 or +5/-10 might be alright. I can tell you this, if I came up behind someone at 5 over, and they slowed down to 10 under (assume the road is a 50MPH limit, that means you were going 55, now you're going 40MPH), I'd be quite annoyed with them, and probably seeking to pass. Yes, not ideal Hypermiler behavior, I know, but I'm a recovering speed fiend, and still carry some of those traits.
I would say to only go 5 under the limit if there are people behind you and it is a 2 lane road for courtesy sake. if there is no one else on the road, go as low as your top gear will let you. I drop out of overdrive around 35-40MPH. I try to stay above that.
Be the change you wish to see in the world
45 mph is the bottom limit of my top gear below that it will downshift (automatic). On backroads I never drop below -5 but on the highway 3 lanes a side I will go -10. This is a fun challenge eek out that last mile out of each gallon.