Dared SL2000a Preamp - What tubes you using?

I bought this little Dared about 6 months ago. I'm not sure how many owners are out there who have really tested this guy, but I'm interested in other's experiences with Tube complements that you found are the best.

The guy I bought mine from had installed 2 NOS Mullard 12AT7's in place of the original cheap Chinese models, and a NOS Bendix 5Y3GT rectifier tube in place of the cheapo 5Z4P.

I had all but decided it was time to upgrade to a "real" tube pre, but this weekend started toying with the Tubes. I swapped out the 12AT7s for 2 other NOS brands (GE, Conrac) with little effect, and the Mullards were the best. Then I pulled the Bugel Boy 5AR4 rectifier tue out of my Fisher integrated and installed it in the Dared. Wow - what a difference.

It's now performing better than most pre's I've tried for more money, but I'm wondering just how much better it can get with better tubes. Anyone out there who can share experience?
I changed to a pair of amperex 7062's which are taller than the std 12at7's and supposed to have a 10,000 hour life. I also changed to a brimar 5z4g. In my opinion the brimar improved the sound the most. All in all, I'm very impressed with the little dared esp considering the cost. The only downside is the remote volume, the volume increments need to be smaller or finer.
I'm using a pair of NOS Mullard CV4024s with a cryo'd Visseaux 5Y3G from Tube World. I've tried a Sylvania 5Y3GTA & a Bendix 6106 & the Visseaux is best so far.