You're not looking for a percentage to have your crit at, your looking for the crit rating. Crit percentage comes from 3 places: crit rating from gear, crit chance increase from main stat, and crit chance increases from the skill tree. Your skill tree additions don't add to you DR, and your main stat DR is theorized to be anywhere from 10k main stat to 25K main stat. Where the actually DR comes in is from crit rating, which starts to get DR around 300 (if I'm not mistaken). In heal spec I was able to get close to 40% crit chance, where as in TK or Balance spec I'm around 35%. Each of the four main specs (Seer, TK, Balance, Hybrid DPS) has a different crit rating they should stack to.
You're surge should almost always be around 75%. The only exception to this (as much as I've researched) is the TK spec, which favors more alacrity than the other specs due to it's abundance of force and cast heavy rotation.
And just to make sure I explain as much as possible, there are two tiers of stats. Mods come with Main stat, Endurance, and a tier 1 stat. Enhancements come with Endurance, a tier 1 stat, and a tier 2 stat. Tier 1 stats include power, crit, defense, and absorbtion. Tier 2 stats include surge, alacrity, accuracy, and shield. Given this info you can only ever trade power for crit (or vice-versa) and surge for alacrity (or vice-versa). Keep this in mind as you are trying to spec out your gear.
In terms of set bonuses, I know when I healed I preferred the 2 piece PVP and the 2 piece PVE set bonuses. The extra 50 force of the 4 piece PVE healing set is nice, but as long as you are executing your rotation correctly you will never run out of force. In DPS spec I roll with the 4 piece Masters. In TK the extra alacrity is pretty important. It also helps in the hybrid DPS spec since you cast tk throw so often.