In light of this:
There are no etiquette restrictions on whether to send a gift before or after the wedding. If before, send it to the bride's address; if after, send it to their joint address.
I tend to do it quickly because without the actual date coming up in my diary I'm more likley to forget.
I say: the giving of the gift is under the total control of the giver. It's the giver's show; the giver's choice of amount, item, etc.
And therefore the giver's completely freedom to send it when it is convenient for the giver.