To my knowledge there is no readily available alternative to the 6H30.
I have heard the 6H30-DR lend a positive improvement (vs the 6H30-EB) in ARC Reference gear, but not so much in a CJ ACT2 or Premier 140. Even then the result was no where as dramatic as, say, swapping contemporary EH 6922s for NOS 6DJ8 family. Strictly my opinion re CJ: at current prices the DR does not warrant the premium over stock. If you still want to spring for the DRs, I've had good results from Eugene at www.conusaudio.com. If you do get them, let us know how they work out for you.
I have heard the 6H30-DR lend a positive improvement (vs the 6H30-EB) in ARC Reference gear, but not so much in a CJ ACT2 or Premier 140. Even then the result was no where as dramatic as, say, swapping contemporary EH 6922s for NOS 6DJ8 family. Strictly my opinion re CJ: at current prices the DR does not warrant the premium over stock. If you still want to spring for the DRs, I've had good results from Eugene at www.conusaudio.com. If you do get them, let us know how they work out for you.