US Airways Dividend Miles - When is $99 Companion Ticket valid for new members?

Hi, new to the forum and tried to find the answer to my question but had no luck...

I recently signed up for the US Airways DM card and received my card last week. I'm waiting on the welcome packet that is supposed to have the companion fare coupon/certificate. My wife and I are taking a trip to Seattle (from DC area) at the beginning of September and haven't booked flights yet. I'm wondering if the companion fare coupon will be usable as soon as I get it IF I have made a purchase using my US Airways card. OR, do they wait until the first statement date to confirm you have made a non-returned purchase and THEN the companion fare is usable?

My thinking is, if I'm lucky enough and the coupon gets here in the next week or so and I've made a purchase on the card, I would be able to book our flights with my wife on the companion fare. But I don't want to wait and miss out on a lower fare if there is no chance of using the companion fare before my first statement date... Does that make sense?

In general, how long does it take to get your welcome packet (they say 2-4 weeks, but just checking to see if that is actually true). I'm definitely cutting it close - I know I have to book 14 days out. Thanks for any help or advice!

IIRC, you should get it fairly soon. But there will be a "not valid before" date on the certificate and I think it is the first day of a month - e.g. Aug01 or Sep01 so that could be an issue. I hope it works out for you!

The certificate also has to be used 14 days in advance of the travel date so you're running into a tight window.