David, most 6L6 vs EL34 comparisons EL34 come out the reverse of what you listed. Then again, EH tubes often sound among them most lush in the spectrum.
Generally, I would stick with the EL34, but try other brands. JJ E34L will come across a lot more as you described the 6L6, and in the right amplifier put forth an absolutely glorious midrange that almost nothing else compares to. JJ and Shuguang EL34 will track closer to what you described the EL34. These three tubes will come in at quite modest cost. EH 6CA7 will present the most slam, though in an easy to live with presentation. Shuguang Black Treasure and old Mullard do sound a better than the others, though at a higher price.
Of course, the amplifier itself plays a role. Your PrimaLuna features autobias, which provides a lot of convenience, though some implementations do not yield as much sonic flexibility as others. I've not lived with a PL amp, so I don't know how they react. With an amp where you adjust the bias, you can sometimes better dial in the tubes to your taste.
