Originally Posted by CrazyOne

That's probably the best option. Best I've found for booking actual Premium is to use the $35 off PC 988713 on the Hertz.com site, with AAA CDP. Results in a $284 and change total. Oddly, booking on the AAA site dropped the F rate another 10 bucks as you found, but their rate for the G was much higher. And you can still put in your ZE1 number looks like and get points.

Probably not much more room with other CDPs. Maybe there's one out there, but it appears a lot of them stop being a good deal after F. I put in USAA 77694, and it was $195 for F and then over $300 for G before any coupons/tax.

Basically, if you book the F with the upgrade coupon you're taking a gamble that you won't get a G. That said, you're saving over 50 bucks vs the actual G reservation, and you probably have a good chance of still getting one. I'd probably go with the upgrade booking, but it really depends upon how desperately you need the G car (for space or whatever reasons).

Good luck.

PS Worth noting that the $35 off is for any class, so if you really could get by with the F, you could shave some more bucks off that reservation instead of getting the upgrade.