The bolt pattern, rotor size, and hub register are all the same. The only difference is the bolt size. On the E hub, it's much smaller of a bolt: (E hub, but H bolt shown)
(you can see damage to the hub's face where i had to use a sharp punch to remove the broken screws that were corroded in. always always always either use anti-sieze OR loctite, to keep the threads clean!)
not only would it open up more parts, but I would have ONE hub to buy for instead of two. parts interchangeability is a BIG thing for me, and doing this also means everything from the E rear wheel can now be swapped to the H, if the need arises.
1 buy a quality 1/4" drill
2 buy a quality 1.25-8 tap
3 lay your H rotor on the E hub to ensure the holes line up
4 remove rotor, and use the E threaded holes as a template and drill right through, taking care to be perpendicular to the hubs surface, and lightly countersink each
5 tap the first hole, careful to keep the tap perpendicular to the hubs surface. you can use anything that is square to check two sides of the tap, 90 degrees from each other, as you start the tap
(i didn't take many pictures, since my hands were gloved and covered with grease/alu shavings, and muck, sorry)
put a glob of grease on the bearing and you won't have to worry about shavings after tapping
because you can pull a rag through from the other side and clear out all the grease / shavings at once.
6 lay the rotor on the hub and tighten the first bolt, then clamp the opposite side so it lays flat. now you have a smooth surface to check for perpendicular.
7 tap each remaining hole, and place each H bolt in as you go
8 remove all bolts, clean holes and bolts, apply loctite, and torque to something or other ft lbs.
8 mark each bolt head with paint pen, for a quick visual check that things are still tight.
9 ride.
now when you need a new rotor your options are greater, cheaper, and swap with your newer H wheels without issue.
Off to my favorite log hoppin spot for a test ride:
and don't forget to periodically check the bolt heads for tightness. oh, yes, quick and easy with those paint pen marks !
:)
.