Thanks for the pictures, they prompted me to investigate these purchase channels further.
Having browsed the sites, I see some of the AliExpress ones on Amazon storefronts. There is a large selection of tents I've never heard of, much to think about there.
Our Big Agnes tents are perfect for a very large proportion of the year but maybe too much mesh for winter. Terra Nova seem to get the proportion perfect in, for example, my Lasercomp - a triangle at each pointy end and half the side door. The MSR Access 1 winter tent goes much too far the other way, just a tiny triangle at the top and the condensation is horrendous.