L-pads are a good idea too, but I felt that would add clutter and complication in front of the amp. I prefer these tucked away in the back. They provide consistent results, and I don't hear any tonal changes on three pairs of cans or on the powered speakers connected to the preamp line out jacks.
These attenuators were about $30 per pair with shipping: https://www.amazon.com/gp/product/B0006N41B0/ In the end SYS would have been a slightly better deal after I bought a second pair, but I like how these take up less space and don't require more cables.
I know what you mean about tidy. Since I can solder, etc. I would have turned on the calculator, bought a few resistors and put together a headphone extension cable that has the LPADs built in. Luckily I don't need this as my headphones are not too sensitive. I've never seen a stereo LPAD that is applicable to headphones that is prebuilt and purchasable, only stuff for loud speakers.