I don't have any information about the chemistry of the latest 2015 or LT32.
I do have some information about someone's success shooting the new 2015.
My friend Marg Garen had a good weekend at Phoenix (Dec 1-2). Shooting both days of a two grand 1-200 yd. five shot unlimited match. She won one of the grands, shooting Canadian 2015 and Berger's Column bullets. Her Saturday morning aggregate was spoiled by extensive research by her and her husband Paul, who shared a rail and bench, on the extent to which perforating your first wind flag enlarges group sizes. (I have it on good authority that they were about 4") That same afternoon, she placed a close second to Tom Libby, and looking at her overall performance, I think that she would have had a really good chance at the "two gun". I think that this is a stellar performance for a relatively new shooter, who has probably been spending more time practicing for her cowboy shooting than with the rail. (cross training?)
http://benchrest.com/showthread.php?84978-Arizona-Invitational-5-Shot-Unlimited-December-1-2
One little tip, that will help prospective users, is that you should plan on cleaning (with bronze brush) between groups, and short stroking the back half of the bore, with an IOSSO loaded nylon brush, at day's end, at a minimum. (One can become spoiled from shooting 133, as compared with just about any other powder.)