This is the exact build I use. It’s got great damage, some utility in the form of Sterea Trofh and Safety Zone, and the ability to cover ground incredibly quickly with the proper transformation. The main benefits you get from Cleric2 are more Heal tiles and Divine Might. I’ve yet to miss either of them.
There are several monsters you want to look for as transformations on this build. @Kannushi is right on the first one. Lapinel is, by far, the easiest of them to get since they spawn in Valandis Room 3 with some regularity. The others are all special Pantos (Red, Blue, Spotted, and just plain Panto) that can only be spawned by an Oracle using the Change skill. They don’t appear anywhere else in the game. I made an Oracle just to get one and was lucky enough to spawn it twice in a period of about two and a half hours.
Also, consider shelling out for a Gray Jukopus gem to boost Transform’s level by 1. You might find it helpful since you won’t have DM.