i haven't succeeded deity yet neither. need some more experience on that level.I am nowhere near Deity yet. I am still working toward winning consistently at Emperor. I find that a Spiritualist leader like Ramesses needs to get religion -- either by conquest or by teching -- at a fairly early point in the game in order to take advantage of the Spiritualist trait. It doesn't make sense to try to beat the military civs at their own game long-term. But once in awhile I do that by playing Ragnar just to improve my military skills. The rush/no rush decision depends on the availability of Horses and whether I have enough decent land for expansion without getting into an early war. That is the most important early decision for Ramesses.
I don't find SPI trait that much useful. Because switching to military civics just when the enemy is in your borders seem so late for me. i prefer a rather active and continous military approach.
for a shrine economy you just don't need SPI trait neither. Any guy starting with mysticism is ok.
Availability of a resource gets much more of an issue in high levels. So you need to build your 2nd city early enough or pick leaders with UUs requiring no resource. For the second city, you should place it just the tile near the resource, you don't have time for culture pop (unless u're CRE)