Just saw this post.
I'd say go for whatever sounds the tightest too. It seems like it would easier to dial in a little bit of balls back in if the Jacksons are perhaps a little too tight, than to have to deal with a flubby lower mid range.
The 24.75 inch scale of the Eclipse definitely doesn't seem like a good idea to me.
If you were to use either the Eclipse of Hellraiser, the Hellraiser seems a much better bet with the 26.5 inch scale, plus the fact that EMG 707s were designed to sound in between EMG 81s and 85s (albeit for 7 string guitars of course), so perhaps wont be as potentially muddy.
Yes so far the winner tonally has been the Hellraiser, but it is a 7 string guitar and it would take some adjustment for the player to get used to.