Robert Tucci Symphonic Concert mouthpieces are based on decades of experience in both performance and manufacturing. They accommodate all types of BBb and CC-tuba, from medium-bore student instruments to those common in large symphonic bands and orchestras. All models are efficient, all offer tonal presence and strong fundamental-based sound to the listeners. They provide the player great control over dynamics and intonation.
I have a Chinese knock-off of the B&S 3099 tuba. I had been using the Yamaha Jim Self signature mouthpiece with it, mostly happy but I struggled with the high register. The RT-64 definitely helps with upper register (in my case only going up to the high F, so far) range and accuracy. Tone quality is great and I think intonation is slightly better. The lower register is a little muddier than with the Jim Self signature mouthpiece, but it's worth the tradeoff.