I had FMB make me a pair of 29er tubs using Furious Fred treads. I don't remember the exact weight, but they were close to 600g each, in a 50mm width. I was unlucky- one punctured on my first ride. Not light, not puncture resistant, no grip, expensive, and no discernable improvement in ride quality over a tubeless set-up.
Don't get me wrong on FMB- their road and 'cross tubs are brilliant. The MTB ones just didn't work out for me. My very poor choice of tread didn't help.
Tape is fine, the only thing you need to worry about is that some tyre's might have weird coatings on the base tape that don't stick too well but you should generally be cleaning that up for normal gluing anyway. I don't think Dugasts ever have that problem
I had just built a new bike and the clinchers I had on order were ages coming. Johnathon from Strada Wheels built me up a pair of tubulars at the last minute so that I could do the 24 Hours of Exposure. I received the wheels the morning of the race so had no option but to use tape. 4 hours into the race the rear tyre rolled off the rim. I managed to borrow a wheel and continued. 2 hours later the front rolled off the rim. Since there was no chance of finding a 29er Lefty wheel to borrow it was game over.
Tape doesn't work in mud.
I was using a pair of 47mm Rhinos (the widest that were available then) and before they rolled I was sliding around all over the place. I think they were just too narrow.
They were mounted on Major Tom rims, which was the widest tubular rim I could find on the market at that time. At anything less than about 40psi both the FMBs and the Rhinos squirmed horribly.
Since then I also picked up the Fast Birds. Compared to my Stans/240 clinchers the tubular wheelset is heavy though, so I've never used them. I doubt they could be any faster than the Schwalbe or Maxxis tubeless.
(OT- thanks to Adrien from Roues-RAR.fr for getting the clincher to me in time for the 24 Hours of Finale Ligure two weeks after the aborted 24H of Exposure!).