Tube recommendations for bass amp

hi All, I'm looking for recommendations for tubes to match some 6k6: 8r Danbury 'super' opt's. They are rated at ~30w from memory. sounds easy? Well it's complicated by what it'll be driving, a bass horn using a 16 ohm driver, either a Richard allan cg12 super or goodmans audiom 61. I've driven similar (slightly smaller) horns with the RA 12 using a SE 4p1l and transcendar opt and it sounds good, -3dB at 37hz.
I'm hoping for even better performance with a push-pull output transformer. The RA has a max rating of 10-15 w, they go loud with 1w so that should be fine.
So I'm looking for a tube that has a decent sized cathode and works well with a 6k load per plate. I'd like to avoid dht's as Im planning to fit 6 channels within a reasonablely compact chassis. No tube comes optimally to my mind?!?
Mid and treble will be powered by pse 6e5p amplifiers via minidsp.

Thanks for the 7591 recommendation, looking at the data sheet it gives 6k6 p-p, so 3k3 per plate, I'd plan to connect my 16r speakers to the only available tap at 8ohms so a reflected impedance of 13k p-p.
I used these opt with some 6av5 triode strapped with a pair of d3a triode strapped and a ccs under the d3a for a very low distortion 8w, if only the opt had 16ohm taps. If I like how it all sounds I'll get some dedicated opt's made but for now I'm trying to work out a simple design to cobble a proof of concept. I have a load of dht's that would work but I'm not going there having just built the choke input coleman regd filiment supplys for my 833a!