It appears that they are either discontinued ot held up for relabelling. I can’t seem to find Vallejo clear sprays, either.
I use only Tamiya & Vallejo acrylic paints (mostly WWII AFV’s). I haven’t used Testor Dullcotes because they are known to be strong. How about Krylon? Michaels and HL have them and they are cheap.
I’ve always had good luck with Testor’s Model Master clear coats, it comes in dull, semi-gloss, and glossy. I use them right out of the rattle can with a very light touch.