OK the secrets out now, I'm in Murano in November and have arranged a visit to the Celotto workshop hoping to pick up a couple of pieces without the huge gallery premiums. The Tagliapietra influence is quite clear and as I'm graduating more towards collecting this type of work at present. I've got a couple of Tagliapietra pieces from his earlier days in the 1980's and it's interesting to see how his work has evolved and become far more complex over the years. I can also recommend the 2 books on his work that are out there with some stunning illustrations if this type of glass is your thing.
Paul