There's an older, much older post here on the Doyle UPS (either in Rigging or Sails). That one is quite detailed and should have a lot of answers.
If the sailmaker thinks that sheeting to the stern cleats should work, it means that the fore-aft distance should be correct to give you a reasonable sheeting angle for that sail. You can always do what I did for my spinnaker blocks, which started out as a quick jury rig to test out a hand-me-down spinnaker, but proved so usable, that there never was a permanent replacement.

I never bothered with a way to cleat the spinnaker sheets in front, mainly because given the circumstances, it's effectively a light wind sail for me.
Unlike what I did, you might like to have a second set of blocks at the front. If you are flying this sail instead of a jib, then you could simply repurpose the jib fairleads and cleats, just that the sheet enters them from the back of the boat instead of the front. (If you want to be able to leave the jib sheets rigged, then you might be able to mount a second car on each jib track.)

My tracks don't have end caps, so I could slide a second car onto them, or even take one car off and add another. Some tracks have end caps, then your only option would be to re-string the block each time, or, alternatively mount a fixed block somewhere between stern cleats and jib fairlead with some way to cleat the sheet for the code 0.
(click on images to enlarge)