Go here:
http://sro.mmosite.com/x/
Find what you want at level 70... then find out HOW much SP you need for it.
Then go here:
http://stud3.tuwien.ac.at/~e0125557/sro/spgain.html
That tells you how much SP you will get with what level gap if you have that gap for the whole level.
Then Ctrl A and copy the table, open up excel and paste. Then delete all info for levels below the level you are. Then sum all the columns from your level to level 70 and find which one has approximatly the amount of SP you require for level 70. Then keep that gap all the way through.
Keep in mind that WHEN you get to level 70 and IF that is before the update ALL you can do is SP farm. So I would do the minimum build possible that will allow you to kill mobs with ease.
Also note that killing BLUE/GREEN mobs is better than killing ORANGE or RED. Unless you have a SOS+3 or SOM etc... That is because BLUE/GREEN mobs are easier to kill so you can kill lots quickly therefore getting more drops since you kill more and using less pots to kill them, therefore getting more xp/sp and more profit.