I don't know if you are familiar with Clematis on the Web, but it's a really nice resource. I used the CotW search form and put in two of your requirements, the anther color and the group (Tangutica). It gave me 4 clematis: Golden Harvest, Treasure Trove, tibetana subsp vernayi var vernayi, and tibetana subsp vernayi var vernayi 'Orange Peel'. Treasure Trove has a dark reddish blush on the outer petals over the yellow and so probably isn't one you want.

Look for Clematis tangutica 'Golden Tiara' (aka 'Kugotia') . It pretty much exactly matches your description