Best tube compliment for use in AI Modulus Three

My last post garnered such excellent advise and recommendations from the wonderful people here at Audiogon, I thought I'd give it another try. To begin, my system consists of an Audible Illusions Modulus Three preamp, Golden Tube SE-100 power amp equipped with Ei KT-90 tubes, a Pioneer Elite PD-54 stable platter CD transport being fed through an MSB Link DAC III DAC, and a pair of Acoustat Spectra 11 hybrid electrostatics. All cabling is MIT MI-330 between components except for a pair of JPS Labs Superconductor Plus cables between the preamp and power amp, and the speaker cables are Audioquest Midnight single wires.
I am extremely happy with the sound being produced by the system right now, but like most of us, I want to get the absolute best performance possible out of the equipment in my system. Which brings me to my question. Right now, I'm using JJ E88CC tubes throughout the preamplifier. The sound is very smooth and well layered, but I'd like a bit more of a lush sound and better, deeper bass. Can anyone recommend a different set of tubes, 6DJ8's, 6922's, or E88CC's that would accomplish my goals? I've been looking into some NOS Amperex Bugle Boys but don't have any actual experience with these tubes. So, I'd appreciate any input you'd care to provide. Thanks in advance, Mike