Affidavits/Proof of Marriage for I-130

[Mme D 22]

Hello All, I am traveling in a few weeks to marry my fiance in his home country (Algeria). We are not having any kind of formal wedding ceremony; we want to do that when he comes here. I have already been there once to get engaged and apply for our marriage certificate. I will be staying there with him for about a month, so I want to prepare everything for the I-130 petition before I go there, email a copy of the marriage certificate home to my mother, and have her mail the petition for me to save time.

My question is, if I get affidavits of a bona fide marriage from family members here, is it okay for them to be signed and dated before the marriage takes place? Can the affidavits be used as proof that they know of our ongoing relationship, and not that they actually attended our wedding ceremony? Or do I need to wait until after the actual date of our marriage? From what I've read so far, there is not much weight to these affidavits anyway; I just don't want them to be totally useless. We don't have that much evidence of a real marriage besides the marriage certificate, my trips to his country, and all our pictures together (both in the US and in Algeria). Any advice on this would be so much appreciated.

Thanks!