Couple options.

If you don't want to boost, having your main invite the first, which then invites the second is viable, then you run around in a team of 3.
X (your acct)>A>B

This allows you to run around in a trio and eat things. I've not gotten confirmation that gifting levels from B to A causes A to generate levels for X, I've asked several times. If they do generate in that fashion the chain is definitely superior to the X>A and X>B arrangement.


If you want to boost, have your wife invite you, accept and create and upgrade that account, which then invites yourself again, then you use your second set of CD keys to activate those.
Y (wife acct)>A>B

This allows you to keep your 70 mage viable as a booster without 'wasting' the grantable levels generated by acct A. Of course if your wife's account is all 60s you may have to get creative

I have a 70 feral on my main account, I had my best friend invite me and then created A>B>C>D, so I can boost and those levels generated by A aren't lost. He also gets the zhevra and the free month.