Recommendations for rolling tubes on Luxman SQ-N10?

The Luxman SQ-N10 is a nice little integrated amp.  I owned one for about 2-3 years but I sold it 4 years ago.  I was using it for a headphone amp and it was excellent for that use.  I rolled tubes but it's been to long for me to remember exactly which tubes I liked.  Typically I like Mullard CV4004 (12AX7) tubes for their warmth and full body sound. 

@nordicnorm - thank you for the response on the Shuguangs. It'll be something to consider down the road when some of my other 12AX7s are done with. For now, I have a handful of decent ones to play with, but thanks for helping me understand em!

@smatsui - Those Mullards were actually started, both in the SQ-N10 and in my previous phono stage. They're a great improvement over most stock tubes for only costing ~$20.

@nordicnorm - just wanted to let you know that I really appreciated the advice you gave about switching the 82 tubes instead of the 84s. Before you posted, I had already ordered a quad of Gold Lion 84s, and after I got them, I wish I had gotten your post because they didn't add any benefit to the sound I was looking for. Instead, I returned them and found a matched pair of PSVane 82s which arrived today. Though they're not broken in yet, they are WORLDS of an improvement in top end detail in comparison to the stock tubes I had in my Luxman. 

The bass issue I had was rectified by a change in cartridge, as I was using a Dynavector 1d73, which was more lean on the bass compared to most other cartridges. I got a huge improvement by moving to an Audio-Technica ART-9, which provides a much more flat response all the way through and is extremely musical. While being less pronounced on the top end detail, the ART-9 got me the bass and dynamic range I wanted while still retaining detail, and these new tubes are stepping in and adding everything else on the top end that I could have wanted. The system is now where I've always wanted it to be, and I am wowed with almost everything I am putting on there.