I want to change the speaker in my hot rod deluxe, the stock one (Fender Special, ¿Eminence?) it's a bit harsh for my tastes and I installed a mojotone greyhound but the cleans are a little too mellow to get that fender clean sound. I'm looking after a speaker that give me enough sparkle to play early Dire Straits but also takes well pedals to get Gilmourish sounds. I've though to get the g12c speaker, but I fear is too bright for the Gilmour distorted tones, and the g12c/s... maybe too dark for that Knopfler sound?
If it were me, I'd go ET65 ... because I find the HRD a bit too harsh. However, since you state you want:"enough sparkle to play early Dire Straits". I'd be a little concerned that the ET65 may be a bit too warm for you.
In your case, I'd go Reaper HP or maybe the G12C/S that you mention. Or, go with the ET65 ... & know that your treble control may end up a bit higher than you have ever had it before :-)
Note that the new George Benson Hot Rod Deluxe (which just came out) is using a 12AT7 in V1 to get a cleaner, less distorted sound - good, which suites Benson's jazz guitar. The 12AX7s are used in V2 and V3.
I went a step further with your recommendation - I used a JJ gold pin 12AT7 in V1 and a gold pin 12AX7 in V2 in my Blues Deluxe Reissue. With the ET65, it sounds fabulous. Gritty and with bite, much like the opening riffs from "Mainline Florida" by Clapton in the drive channel using the bridge pup on a Fender Strat.