I am basing all my figures on 25mm magnetic round bases.
Here is the link to Stephen's website, it has not been update in a long time, but he does have a lot of YouTube content, which in some of the older clips, shows the big bases close up.
Those big unit stands in Stephen Smith's AAR look great.
:-*
(https://2.bp.blogspot.com/-8XfI3XkI-i8/W3dSpDzRG8I/AAAAAAAAPVQ/hbjVgtXQcIU5RDlRk7zFQSM0DrK_yfgzwCLcBGAs/s1600/20180817_112804.jpg)
(https://3.bp.blogspot.com/-KpDOPFHQ1O4/W3UX3tYwzaI/AAAAAAAAPTQ/wAENdduJjoMAYYJsV6fCsaXhODvrNUxkgCLcBGAs/s1600/20180816_002704.jpg)
I mount all of my minis on pennies and make sabot bases to accept the penny. That way if I decide to change rules all I have to do is make new sabot bases. https://antonswargame.blogspot.com/2018/08/diy-sabot-bases-using-proxxon-hotwire.html (https://antonswargame.blogspot.com/2018/08/diy-sabot-bases-using-proxxon-hotwire.html)
further info here https://antonswargame.blogspot.com/2018/08/blue-board-sabot-bases-completed.html (https://antonswargame.blogspot.com/2018/08/blue-board-sabot-bases-completed.html)
Some of those larger bases look as though they could be Simon's To The Strongest originally? I like the irregular edging on these bases.
Cheers
Tony
Link if not seen the bases before
https://bigredbatshop.co.uk/collections/all?page=7 (https://bigredbatshop.co.uk/collections/all?page=7)