Working topology for Eurasian population structure

Here's my new "basic" qpGraph topology that I'll be using to test phylogenetic and mixture models for Eurasians. I think it reconciles a few key findings from recent scientific literature. Please note that since my main interest is post-Neolithic prehistory of West Eurasia, and in particular the early Indo-European expansions, I don't want to make this model unnecessarily complex by adding "dead end" Upper Paleolithic genomes.

But I welcome ideas on how to improve and make use of this topology, so if, say, adding Ust_Ishim helps, then let's do it. The ancient samples featured in the above graph are listed here and the graph file is available here. Feel free to post your own versions of the graph file in the comments and I'll run them as soon as possible. But please remember to label the samples correctly at all times.

Update 13/07/2017: Thanks to Matt in the comments, here's a neater version of the same model, with a lower (highest) Z score and slightly different mixture coefficients. It includes a couple of zero edges, which are generally undesirable, but these might disappear when more populations are added to the topology. The graph file is available here.