Should i just use cloth with int and spi or mail that has usualy str or sta

As a healer you are going to mainly want gear with Spirit, Intelligence or MP+ stats. If all you're doing is healing then where whichever gear has more of those stats because you will not be hit by attacks very often.

The strength and stamina gear is only if you want to do some up close and personal damage.

From levels 1-80 focus on intellect.
From 81-85 focus on spirit.

At 85 when you wanna start doing heroics you gotta reforge crit or haste and keep them in balance. Whatever you feel works for you. For instance if you feel your heals arent shooting off fast enough to save some people, reforge crit into haste. If your running out of mana even when people use crowd control, spirit.

Theirs plenty of debate on whats right and wrong but i can only say what worked for me.
My crit was around 9% and hast was 10% and my spirit regen was 3000-ish if i remember correctly. Healed heroics like cake. Any healing before 81 is pretty much just intel and spirit if it comes with it but dont worry if it doesnt.

Look up mmo-champion.com on the forums, some helpful people there.