Dude,
Generally, you will save processing time if you can use the DCF method.
However, keep in mind that you will have to establish domicile in the US before she can get a visa and possibly before they will accept your I-864 Affidavit of Support. This usually means that you will need a US residence and employment with a minimum qualifying income. So, I would figure on returning to the States ahead of your wife anyway if you don’t already have permanent employment and domicile established.
I know of one individual living overseas who filed the DCF and her visa was held up until he returned to the US, established domicile, and provided evidence of steady employment for a minimum of 3 months. The bottom line…he didn’t save any time in the long run by filing overseas.
Contact the US consulate over there directly to check eligibility rules and filing details.
Ray