PeterH

I've got a girlfriend who has signed up for a Dawn Candy workshop, on the materials list she said she uses Amaco Velvets but can use other brands. Sean O'Connel's website has the glaze recipe he uses from 2018 as Campana Clear. I've tested that glaze, it is fluid.  (contains zinc so chrome green stains in green underglazes are going to go muddy)

If you notice both examples of running/bleeding you posted are blue, most likely a cobalt (carbonate or oxide) wash rather than an underglaze. If you are after blue, I would use a cobalt wash rather than underglaze. Unless it is very thinly applied, cobalt will have a tendency to run or bleed. 

Friends In Clay,,,,,,Periodically it's a good idea for us to remind all forum users, whether you are an active participant, an occasional contributor, or a lurker, to always take advice, especially technical advice, with care. I have not doubt that everyone who gives technical advice is doing so with the best intentions, but you must do your own due diligence by doing additional research into your question. Then, test, test, test,,,,,
 
best to all,
Steven