Yeah, your Trailblazer isn't really cut out for CAC. Likely, you would burn it up if you kept pushing it maxed out like that. I have welded with the big Miller inverter based engine drives & I'm not crazy about them. There's been lots of reported electronic problems with the 304 & I knew a dude with a Du OP & he had a ton of engine trouble with it. From what I have heard, the Vantage is a much better machine & I'm a Miller guy. Lots & lots of them on pipe jobs & I've yet to hear anything bad about them. But, if you already have a lot of Miller stuff like remotes, HF box, feeder, then stick with a Blue machine.
To answer your question about the 30A, yes, it does a fantastic job running off a Miller engine drive. I use mine for field repairs often (running a TB 302) & It's always welded super. I don't do the big stuff working for myself, so the toy machine I have is more than adequate for what I do.
Good luck! S.W.