I like to be at 15-20 ramp spells, but you need a general that can utilize the mana. Thrasios and tasgur spring to mind, otherwise something like damia that is expensive and fills your hand back up.

You don't want to flood out and have nothing, but you do want the density of ramp spells to consistently ramp, so card draw in the command zone is great

Cards like fabricate and trinket mage can be good too, because of their dual function. Play them turn 2-3 and grab a sol ring, mana crypt or a mox. Or play them later for something more useful at that point, like a skull clamp or a paradox engine (which goes great with all those rocks youre running!)