By 0 spd, do you mean '0 agi'? Anyway if I were you I'd make the lvl 180 with a mainly AGI stats+ some WIS that is just enough to cast Stone Wall on your other characters. I said this because an earth of this build will have low INT, so you're not going to have your hopes high that the earth will be able to cast Tree Bind and/or Terra and it succesfully seals. At level 180 and 100 AGI though, your earth will have a naked spd of 468. Even if you do rebirth him as a Knight (and assuming you added the extra 3 points to AGI, making the earth to have 103 AGI), your spd (including the +63 spd of the cape) is still 586.

tl;dr You'll still need EQs to help you reach 900+ spd on your earth (or more than 100 AGI).