Hello Hekowee,
A few things occur to me. Whether your Telefunken PCC88s are made by Telefunken, or Siemens (the Siemens will have a straight copper wire riser up to the hallow getter), both are good at spacial and harmonic information, but especially the Siemens. With less "warmth" in the balance of the sound, it tends to be exceptionally clear and extended for the type. This will bring up the tube set if it is a little dark, muddled, lacking in shimmer, clarity, articulation...these things also positively effecting the soundstage saturation and placement. Also early Phillips PCC88s are inexpensive in general (often cheap!), and tend to be clear for the type, though not as extended and clear as Siemens.
If yours are Siemens made, you can often find pairs of them pretty inexpensively on Ebay, though not labelled Telefunken. I have bought them from European sellers who had excellent ratings without issues.
Tungsram PCC88's can be pretty nice tubes, but balance more toward warmth compared to many of the type, so in this case probably would need more clear tubes otherwise for you to really enjoy them. If clarity, harmonics and the like, things that contribute to "holographic" sound (and nice cymbals), are less than you would like, I suspect these qualities could be brought up by changing any of your current tubes toward better space and fine detail. I have not heard Tubestore Preferred EL34s, but the Shuguang EL34s I have had (I think they were called EL34B having a fattish bottle), were nice and open sounding tubes. Of course that does not mean the Preferred will be as open and clear, but they may be from reports, so I might look elsewhere for now. Don't know about these, but I find many power tubes in particular can take quite a lot longer than 50 hours to come out fully.
In my experience the Phillips 5R4GYS or Shuguang 274Bs are OK at spacial information and clarity but not the best. The 5R4GY tends to be more articulate, punchy and spacious in general, and the Phillips fits this, though a little veiled to me.
Here is a link for a 5R4GY that is notably more open and clear, depending on everything else, perhaps enough to make the Tungsrams open up nicely in your setting.
https://www.langrex.co.uk/products/5r4gycv717-fivre-nos/ The value of the pound pretty good for us now, I think it is a pretty nice value too. Also Phillips made GZ32s, though generally much more expensive, compared to the tubes you have used, will balance more toward clarity and dynamics, usually with a less pronounced bass in the balance, but nice and tight. If you like the dynamics and increased articulation and spaciousness of the Phillips 5R4 over the Preferred 274B, either of these might move you in the direction you want.
Hard to guess when it comes right down to the fine details of enjoyment and balance, all our systems different, but roughly speaking, comparative tube traits convey across Decware amps. At least a start. Anyway, the Fivre might be worth a look based on your comments and hopes for your system balancing at the moment.