Thunderbolt usage is debatable. Although Thunderbolt gets 100% accuracy, Thunder does a better job of getting clean KOs. Of course, the 70% accuracy translates to roughly 10% accuracy when you really
need it to hit.
I wouldn't exactly drop Calm Mind from the set. Quoting from Smogon...
After a single Calm Mind, Latios reaches a jaw-dropping 808 Special Attack stat, and is capable of OHKOing or 2HKOing most of the commonly seen Uber Pokemon.
You can instantly give yourself a boost of something around 200 Sp. Atk with one round of setting up (try switching into an opponent who is choice banding a less effective move, or just has bad typing), and then go on to sweep with Dragon Pulse. The great thing about the move is that only one type resists it, and you get STAB- so you can just use it over and over to consistently KO.
I've never heard of a Latios set with Ice Beam. It actually sounds like a decent idea. On the other hand, dropping Recover can seriously hamper your ability to set up.