The standard Colortune kit with the high tension extension and view scope should have everything you need to use it on an X...
In my opinion the Colortune device is one of those tools that's fun and interesting to use, but I question its real value. I bought mine quite a few years ago, use it occasionally, but it spends most of its time in the box. I never found it any more accurate at carb tuning than the old-fashioned "lean-drop" method where all you need is a good tach (or ear). Also, it obviously can't be used under load so its limited to idle mixture checks.
...and its not a substitute for a CO meter, so its not very good for emissions tuning (although it will put you in the ballpark, but as I've already said you could probably do just as well by ear).
The last time I saw a price, they were in the $50 - $60 range... personally I think that amount could be better spent elsewhere.