Had my main to help level my FS cleric. Going full spirit so leveling cure and heal tile damage is useless. Best is to get pardoner buffs along with a +10 sword and +6 set of cafrisun armor (+ gloves most important for accuracy). At level 15 (cleric 1 priest 1) maxed out the blessing skill since pardoner blessing buff is very limited and this really pushes your low level dps, sucks later on but ktos might save this skill. This should keep you going pretty well till about 140 then you need to just push yourself past the 186 rest, it will be painful solo.
[quote=“c2gaming, post:38, topic:153696”]
As for your title question. The answer would be “no”. I once had a chaplain with lv 3 (not even lv 5) [heal] and lv 5 (not even lv 10) [mass heal]. It is only necessary for a stupid party (that or you are doing ET).
[/quote]You did have Priest3 though, without it Cleric2 is nearly required, and Heal10 is considerably easier to use if you’re new to the game. OP would likely to face trouble without Cleric2, because not enough experience healing.
From my experience, going Cleric1 > Priest1 > Priest2 > Cleric2 had an easy time leveling and i had fun playing support and I can go solo like some badass too 
. My SP never went below 30% and I went full dex build.
Cleric2 is necessary if you want to be legit support for its max level heal 10/10. Those heal carpet ease the pain of our meat shield. Priest2 will help you leveling solo and obviously will be a boon for any party because of the Blessing Aspersion and Sacrament skill.
Plus, Revive and Resurrection will help supporting those with reckless abandon. Mass heal skill is good when in dire situation
Get Cafrisun set if you havent already. Its easy to farm with 100% drop rate. Dont worry about bot running around the area because i havent seen one nowadays or at least scarce.
Level the priest attribute first especially Blessing attributes. And get pet! It can act as a bait or punchbag for mob. I love my Deadmeat.