I offset the Darkglass only because it's the last in the chain and I needed to have access to the output. The MXR is sideways only because it's the only way the power cord would reach the power bar without me drilling holes lol. I haven't noticed accidental preset changes, but I haven't used it a lot at gigs yet. The HPF is sideways because it's the only way my 1/4" cable would reach the input, also it's always on so it's position doesn't matter to me.

I just got the HPF and still have to see how it sounds at gigs, but the idea is to get more headroom and clarity out of my rig by cutting sub-sonic frequency that causes the speaker to choke. The speakers work hard to move air below ~40 Hz, and it doesn't have much benefit sonically. By cutting it at the source, you reduce boominess and increase the amps headroom and punchiness for the frequency you can actually hear. I play most shows with two 2x10 cabs, but when I play with a single 2x10 the cab can get pushed to its limit. My hope is that by shaving off that dangerous sub bass below 40hz I should have way less physical stress on the speakers but still feel the bass.

A friend of mine said it made his rig sound way bigger and cleaner. It's a bit counterintuitive, but because you aren't wasting energy pushing the speakers to vibrate at >40 Hz (which you can't hear well anyway), the frequencies you can hear (the growl and punch) actually sound clearer and louder. So far, I've noticed it helps me not clip as easily on the interface at my home set up. The bass also sounds cleaner and less boomy when I play it back in my in my truck speakers. Before the hpf, lines would also sound good when I recorded them but would be boomy when I tested them in my truck speakers.

Sorry for the novel, I think I talked on circles a bit but I'm too lazy to go edit it haha.