Hey Mark, Technically you can chain them, but it's not an ideal pairing. There isn't a great answer for which to put first, either way you're going to be making sacrifices. Ideally the "Tone" effect and any Harmony/Doubling effects should be very first in the chain. You won't be able to effectively use the D1's doubling and the G-XT's harmony effects together. The G-XT should be last if you're using reverb or echo, but then Tone isn't first in the chain. Ugh, yeah sorry there really isn't a solid answer, I think this will just take experimentation on your part and figuring out which effects you prioritize.