for your visa signature card, i don't think the credit bureaus assume a limit for it for utilization purposes for 12 months.
so i think it either A. tanks your FICOs right away while your "credit line" is estimated and is set at a default of zero (which may be why people are so wary of the world MC/visa signature cards) or B. it just doesn't do anything for 12 months and acts as a zero in your overall util but doesn't count against you for using 100% of your available credit on a particular card (i think if any one of your cards is maxed out, it's definitely a ding for your FICOs).
this i really don't know and someone else should clarify.
this is slightly off-topic, but do you mind me asking what your FICOs are? I'm very interested in getting this particular card and I'm wondering how difficult it is to get (I'd like to apply once the fact I'm paying down my balances has reported).
yes. someone who knows more please clarify and or correct this post.