reshaping the neck heel is only a cosmetic issue -- a Warmoth neck will never fit an RG body because the neck length and scale length don't match..
Strat scale length, 25.5" from nut to bridge, and Strat neck length with either 21 or 22 frets, are the standard dimensions used by most custom builders including Warmoth. RGs have the same scale length but a 24 fret neck, which is longer to accomidate those extra frets. Ibanez bodies have the neck pocket closer to the bridge to make the scale length still come out at 25.5" with the longer neck. if you put a Warmoth Strat neck on there, even though it is the same scale length of 25.5", the neck would be too close to the bridge on the RG body, the actual scale length would be something like 25", and the guitar would not intonate at all. it would be unplayable.
you might think that Warmoth's 24 fret necks and bodies, different from their Strat bodies, would work with Ibanez parts, but Warmoth uses short Gibson 24.75" scale length for their 24 fret stuff. this won't work with Ibanez parts either.
you would need a neck specifically made to accomidate the RG body to the right scale length. like jono says, there are custom builders advertising on Jemsite who have the dimensions of Ibanez parts and could biuld you one with ease and skill.