The 6dj8 family of tubes, to which your e88cc belongs, will probably have, as a group, a very different sound signature in your preamp's circuit than the 12_7's that have been recommended so far. Why not first stick to the family of tubes that you currently use, just one with a tonality more to your liking? With that in mind, and to address your specific concerns, I have found that in MY line stage the USA Amperex 6922 like these http://app.audiogon.com/listings/amperex-6922-e88cc-tested-new-best-used-tubes give me a similar tonality, with similar amount of detail, but less aggressive up top than my Phillips SQ's.
If you want to spend some money look for some USA Amperex 6922 white label PQ's. Good luck.
If you want to spend some money look for some USA Amperex 6922 white label PQ's. Good luck.