If you're in doubt, wait!
I got my first good quality pearls this year. I was happy with freshwater rather than akoya, but I did make the decision to buy Freshadama. I nearly bought the 7.5-8mm, but ended up waiting for the Mothers Day sale and got 20% off, so I bought my dream size - 8.5-9mm. For reference that's the size of Jackie Kennedy's famous double strand.
I think wait for your perfect strand. There will likely be a good sale around Christmas if you can hold out...
Btw I love the suggestion of a long strand. I want one myself at some point. You could wear the rope as a double strand, long, knotted.... PP can even make one up for you with hidden clasps (screwed into a pearl) so the clasps are invisible, and then you can have several clasps spaced so you can take your rope apart into a couple of separate, differently lengthed strands plus a bracelet