Hmmmm, may be just a bit too long with the cable coming out to fit properly. I use a surge protecter similar to this one
BELKIN 820UK Surge Protector buy online | Currys Shorter length and the cable can wind around it in the rack lid.
Basically drilled two holes above and below either side and strapped in with the big cable ties. Tried glue and all sorts before to make it fit snuggly into the lid but cable tie-ing is probably the best.
If the Axe II is 14" depth then it'll just reach the end of the rack, and it's best to factor that the power strip and plugs will take up the depth of the lid, so I'd probably go for the extra 1" that the custom size would give you. At least with right angled cables you may be able to leave them in whilst packing down.