Sorlowski - give the Bendix a try. It is a somewhat inexpensive tube too.
The WE350B's are not exactly warm on their own but when paired with the GZ tubes, they can be...
The Early(1950's) RCA 5V4G (ST Shaped - black base) tubes are a more open sounding rectifiers. I think these are available NOS for under 35 bucks.
I think the GZ34's (as well as most other Mullard GZ tubes) are too muddy sounding. While the Metal base GZ34 is one of the best rectifier choices it pales in comparison to the Bendix.
Now.. when I first got the Bendix, I hated it. It did something strange to the pace of the music - everything seemed awkward. I think others who tried the Bendix at about that time had similar experiences. Once I burned in the Bendix though, everything came into focus. The Bendix is on the warmer side of neutral but the bass is tight, detail is there, the dimensionality increases substantially. Pace is correct. Its a great tube.
Like I said above. Burn in the Bendix. Just disconnect the power supply from the line stage, insert the Bendix and let it cook for a week or more. Every day or so, give it a listen and eventually it will outperform anything else and stop sounding weird.
Another good thing about the Bendix is that it's a slow starting tube and does not stress out the other tubes when it heats up. Some of the Mullard GZ's start fast and in some cases blow fuses on Supratek's. This stresses out the other tubes and shortens their lifespan.
The Ken Rads are good tubes - very organic -rich and warm. Changing these with Raytheon VT231 or Tung Sol Rounds will add more transparency & detail but you will lose some of the midrange magic, weight and round-ness you like with the Ken Rads.
Another possibility is the RCA 5692 red base tubes. I really wanted to like these tubes because they do many things well but for my system I felt they were too detailed and I personaly loved the warmth of the Ken Rads / sweetness of the Tung Sols. If the rest of your system is warm sounding, the 5692's might work for you. Great bass, good detail and dimensionality.. just not "luxurious" or romantic.