SYE for 242 (q about spline count)

I am not to XJ savvy, and Im lookin at purchasing an 89 a buddy has. It has the 242 case, behind what I can assume is an AW4. 3 quick questions, after Ive tried to sift through all the worthless nonsense using search:
1. What is the spline count on the original 242 output shaft (I thought I remeber reading in a rag that it was 32 spline as opposed to the 231??? If so, how are the guys using a cheap ass hack and tap??)
2. What are the options for am SYE, that I dont have to invest real money into?? (Im going ATLAS after a bit. If I purchase it, its gettin HP 60s front and rear, and Id like to wheel it while improving it, so I still need a tcase!!!!!)
3. What are the inherent weakness of the 242 case when used in 4lo in hard wheeling???

It's most likely a 21 spline as opposed to a 23 being an '89 with a 242, think they might have changed '91ish.

Currie, Tom Woods should have slip yoke eliminators for that t-case, I don't think anyone makes a hack-and-tap for it.

231 might be slightly superior as far as strength goes, but the real advantage of the 231 is the after market support, HD chains, gear options, etc. The 242 doesn't have as many options.

Edit: Just noted you're talking output shaft, sorry, haven't had my coffee yet. As far as a hach-and-tap, RE has one:

http://www.polytropia.com/cherokee/sye.html

The output shaft spline count is identical for the 231 and the 242!