EL84 Tubes for Glow Audio Amplifier

Two years ago I built some custom 2.8 cubic foot speaker cabinets for top of the line Audio Nirvana 8" Alnico full range drivers, which I put in my approximately 16 x 20 bedroom. These are super efficient 96+ speakers that don't need much power. I was using my back-up 200 watt B&K Sonata Mono Amps to drive them, which was over-kill. I recently purchased a Glow Audio Amplifier, which produces 5 watts per channel. The stock EL84 Chinese tubes in the Glow Audio were not very good sounding compared to the B&Ks.

I purchased the new production EL84 Mullard tubes, which Glow Audio has on their site as an upgrade. These Mullards did make a night and day difference and really do sound great with Patricia Barber and other jazz singers/groups on both my Denon 110 Anniv and tube modified Oppo SACD players (each player has different characteristics that I like for different music). 

I have not tried any other EL84 tubes on the market to know if there is more to hear. I was going to buy more back-up Mullard tubes, but was wondering if there were recommendations for something else. I haven't found many reviews for the EL84 tubes, except related to use with guitar amps.

Because of past problems with purchasing NOS tubes, please don't steer me that way. I really would like to know if there are any new production EL84 tube recommendations.