Pointe competition help?

I have my nationals competition the week after next and my pointe shoes are dead so I need to order some new ones. The type I currently get (Grishko Elite size 6 x hard shank, they have a wide platform), I am used to very much and have been using that type for 6 years, but they do not support my foot type that well, and they look awkward on my feet (Very high arch, long toes/foot, thin). I saw some pointe shoes that seem that they would work a lot better with my feet and support them (Grishko Maya size 6 xx 3/4 hard shank, they have a medium platform). I have no problem breaking in pointe shoes (Only takes 1/2 hr for me) but I am worried about getting used to them in a week. I need to order them by phone tomorrow morning to get them ASAP so I have no time to talk to my ballet instructor about it. What are your guys' opinions on the subject?