Best current production power tubes for VTL MB 250.

I would like some opinions of the best power tubes for my VTL MB 250 amps. This amp was originally a 225 & was upgraded to the 250 with the signature transformers by the previous owner.  I don't want to spend the big bucks of NOS. I like powerful bass & lots of sparkle at the top end without harshness. Any suggestions? Thanks Ivan