Yeah, I think the Rocket series are something Celestion made specifically for batch orders from amp manufacturers. I think Traynor uses Rockets in some of their amps.
I think you'll find the Texas Heat is a very noticeable improvement. I'm very pleasantly surprised with mine. I've been fairly impressed with any Eminence that has a lower sensitivity rating. Very smooth.
Let us know what you end up with and how you like the change.

