I am a fairly recent Doshi owner so I may not have the wealth of experience that others have. However, I have yet to listen to a single tube combination in which the Alaap doesn't fantastic. (i.e. I don't think you can go wrong with whatever you choose).
That being said, I have it on good authority that the best of the new production tubes are:
JJ gold pin ECC83S
JJ gold pin 12AT7
JJ gold pin ECC99
The ECC99 wouldn't apply to you unless have the separate Alaap line stage or full function preamp.
I recently bought the above tubes for my Alaap and they all sound incredible.
Chris
p.s. Like everyone has said before me, Nick is truly wonderful to deal with.