There is no need for size 10 (6mm) needles in addition to 10 1/2 (6.5mm). Check your gauge first, and if it works on one of the needle sizes, use those needles for the whole project.
You might want to use 24" long circular needles for the main piece and a set of short straight needles (the same size) for the straps.
Pattern has a typo; it should say "or" instead of "and" under "Materials" for the needle suggestion...
This piece is very flattering for all body types. You can wear it with leggings and as a layering piece over a long or short sleeve tank.
Happy Knitting!
