I just did a few things to a newish Chinese B&S 795 (C - similar in appearance to 995)

[bloke]

I aligned the #1 outside slide tubes and put them in the same plane so that the owner could use valve oil on that slide and not gunk up his first and second pistons with migrated grease, I vented the #1 piston, I cleaned some corrosion off of the rotor which could have formed due to solder acid (??), but it was not terrible, though enough to cause the rotor to grind and stick, and I took out a few dinks from the bell flare...

... and then I played it.

Like quite a few of the other tubas that look a whole bunch of like a Nirschl, it is not one. As surely known, I always find tuning things to be the most annoying, and the average position for first valve pitches is in almost two inches (#1 slide) from where the average position is for first and second valve pitches, and third valve is not a viable alternate. I guess it's okay for some people, and it's pretty well made.

Don't judge the fact that the first slide needed aftermarket aligning, that's par for the course with most makes in most all price ranges.

I guess I'm really broken in hard on B-flat instruments by now: Pulling my F tuba out and hitting some studies, I was accidentally mashing B-flat tuba fingerings every once in awhile, and - every time I play any C tuba these days - they all sort of feel to me like they leak a little bit (yet they don't), due to the short expanding bugle compared to B-flat.