I usually record my mic'd amp, but I can only do that at certain times of day and I figure I can run my guitar straight into the Hi-Z 'Guitar' input (that I just discovered on my mixing board after owning it for 5 years *facepalm*), record that, and then re-amp when the neighbors aren't around.

The problem is, I don't have a reamping box, and from what I've read, I need that to convert the recorded signal back into a Hi-Z signal or my amp's gonna blow up (yeah, I doubt that, but people are dramatic on the internet and I'm not trying to buy a new amp anytime soon).

So, in reading the manual for my mixing board (Allen&Heath ZED10FX), I found out there's a -30Db switch hidden away for the mixer-outs (I guess to connect it to another mixer?). Both are XLR out. Can I run an XLR cable with one of those XLR->TS converter things with the -30Db switch engaged to my amp? Or is that not getting rid of the problem at all (besides the difference in loudness between a Low-Z and High-Z signal)?

Sorry, I'm kinda a n00b with most of this stuff and this impedance stuff makes my head hurt every time I try to read about it (and I never understand any better). If just buying a reamping box is better, I've run out of projects and I saw a pretty cool DIY reamping box I wouldn't mind putting together.
You're not gonna blow your amp running a line signal into it.
My amp didn't blow at least.

You can try running a cable from whatever line output of your mixer and see how it like it.
Some amps will take it just fine, some won't, and it's not really a matter of levels, it's a matter of impedance.

So, yeah, try your idea, which could work, and if that doesn't work use a ramping box.

Also I wouldn't engage the output pad in any case.
A line out has (ideally) an impedance of 600ohm, while a guitar amp's in has an impedance between 47kOhm and 1MOhm, so even though line signals are much stronger than instrument ones you're gonna loose a shit ton of it and you're likely gonna need all you can get.
Name's Luca.

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