Good call, you wouldn't make it. If it's a weekday (which it must be, to take the tour) 0830 on I-5 is going to have a bit of traffic (although going North wouldn't be too bad once you clear downtown). And in my experence, the tour never only lasts 60 minutes, it always seems like it starts late or we have to wait for another group in the huge elevator, or something. My recollection is more like 90 minutes.