I've never had issues with cold and using Dullcote, but there again my basement isn't exactly working outside, I've been using Dullcote for about 8 years and swear by it, I've got and tried all the other dullcotes and varnishes, AK, Ammo, Vallejo, Tamiya etc I probably have them all and all the other pretenders, nothing has come close to Dullcote in ease of use over any surface. Maybe it's because I mist it on through my airbrush, usually cut to 50/50 with cellulose lacquer thinner, I don't know but all I know is it's really good, and I'd be happy to stand my stuff up as witness
I use the dullcote and glosscote and never had problems with either
I mix it 50/50 with Tamiya X-20A, yes I know its acrylic thinner but when I bought the testors I didn't know it was lacquer lol.
I still have no issues with it at all and all of my paint is with acrylics, 99% of which are tamiya
It does you can go too quickly. But working more and more with paints that fit that style of application its something that quickly fits in with that approach and they always give excellent results.
And Ive found the AK option easier to get.
I suppose that's its all about, I was lucky I guess in that I've not had any issues with any of the paint systems I've tried. I've got a heap of real colour but not used any of them as yet so I can't speak for them.