FYI to anybody interested - a few weeks ago I ordered the Bolton 35A upgrade kit for my MiniST, with expected shipments to begin for this batch in January. Just got an email that mine has been shipped, with a USPS tracking number. I'm not too eager to work on this now in a freezing garage and was planning to install it after my Rad warranty expires in March anyway, but it'll be nice to have it in hand for planning the swap.
A nice pleasant surprise in a time of delays and shortages, so if you've ordered one or are thinking about it, looks like they're ahead of schedule; their webpage still says January, by the way.
https://boltonebikes.com/collections/motor-controllers-and-displays/products/2019-radpower-upgrade-kit-with-tail-light