Don't bother with dryogenic valves, they are snake oil. Just get some nice preamp valves.
When you say 'Gold Lion' I guess you mean the reissue, Joe Garcia has tried some and they broke. Not sure if it was the valves or the amp though. Anyway, not heard that they are a patch on the originals. It should probably have KT77s, but earlier ones were EL34, not that the circuit will differ, but what is the power rating? EL34 would be 50w, KT77 would be 70, I think, there is a [url="http://www.burmanamps.fsnet.co.uk/"]Burman fansite[/url] and the chap from that is communicative if you email him, can probably sort a manual for you too.
Burman said that just put good valves in, the circuit gives the tone, valves are like light bulbs, some will break and some will be fine. I'd go for KT77 still. If you really want authentic, you can have the pair of original Gold Lions from my Burman Pro502 for £300.
No real reason for an alnico speaker really.