I did two monks at the same time
C1-P3 and C2-D2 after they both reached around 150-155 I stopped playing P3 and only play Diev one. This is my personal preference. Also if you are going to solo play I would recommend to get a bit DEX.
On priest you will have moonstrance which adds % of your total dex which is an amazing skill at lv1
I would say I am happy with my 170 DEX at level 173, thinking to get it to 200 and stop and focus on STR.
My stat build is this: around 200 DEX rest STR. all the bonus points from quests and statues go to CON.
And seriously there is no need to get aspersio to 10 since if you want to do damage you will have to NOT level SPR and aspersio scales with spirit. Also in the future patches Blessing will add some of your SPR and INT to bonus damage, so it might be a waste going into Monk after Priest.
I will tell you this, Diev is super fun to play (very personal opinion). You get pierce type attack with Carve Attack that does bonus damage on the tree in sauilai mission and most bosses and large targets are weaker to pierce attacks.
You can -20% of your energy blast CD which is insanely good.
Carve OWL can get bonus damage when you are using mace (most maces add magic attack)
And overall Diev does bring good utility to the party.
As of Priest build, most people take it to 3 to get Stone Skin and Maxed out mass heal and revive.
But EVERYTHING i said above is subjective to my personal test and my personal feel of class. I have not gotten any monks past 200 and people do not lie, there is a LOT of monks past 125, like every map has 1-2