Sporterized '17 Enfields could use mounts made for the Remington model 30 rifle. The Rem m30 is and was a civilian model of the '17 Enfield. The rear sight "ears" were removed & the area rounded. That would be a good place to start. Brownells stocks the Weaver mounts, (#11). Depending upon how much the rear of the receiver has been modified / rounded, you may need to shim the front or the rear to gain proper scope leveling.
It took me several trys to get my '17 Enfield on paper.
Roger
