There is no set of mastery you should really shot for. As long as you hold your haste cap, you can have as much mastery as you want. Haste expends more mana while Mastery technically conserves it by healing for more.
Some of your reforging is a bit confusing. You want more mastery and want to drop spirit because you feel its high, but on your neck, you did the opposite. So here is a list of what I would do. Now this is personal preference, but I always enjoy going over the 2005 cap so you have plenty of wiggle room for gear upgrades.
neck: no reforge
cloak: spirit - mastery
bracers: spirit - mastery
Pants: spirit - haste
Ring1: spirit - mastery
Ring 2: spirit - haste
Relic: no reforge
weapon: spirit - mastery
offhand: spirit - mastery
This will help you gain more mastery. If you begin to hurt for mana, you can remove the Spirit - Mastery reforges.
As for the t13, I suggest getting two pieces first before switching any gear out that would break your 4pc t12. The last thing I would add is a question. Why 2/3 Gift of the Earth Mother?