Dear George: If you have the standard version of the Phono cube then it will be better the low output version of your Glider cartridge, this one has an internal impedance of 13 ohms. Other alternative is to change the Phono cube version for the high gain model.
The problem in the high frecuency reproduction is not a cartridge problem: it is a 47 labs system problem, you can read severals reviews about it.
I agree with what Sean told you about a proper installation: tonearm/ loading impedance/VTA-SRA.
You don't need to change your tonearm it is ok ( I own one of this tonearm ) and works best than SME with the Benz cartridges.
Btw, Doug, Paul and Sean: I own the Ruby 2 and the LP Benz cartridges and I never experienced that lost in the top end, I think that the people that has that problem is because a mismatching analog system and not because the Benz Micro cartridges. I think that the people that has that problem are using tube electronics.
George don't go with the " Denon 103 myth ", this cartridge
was an " ok cartridge " more than 20 years ago, but by any music reproduction standards it is a bad music reproduction transducer, it never was and state of the art cartridge by any standards and it never will.
Doug: the Graham tonearm has many problems, specially with low compliance cartridges, not because is a unipivot tonearm but because is a bad design.
Regards and always enjoy the music.
Raul.