Our experience with red sex link roo's is that they are skinny and don't make good meat birds. They dressed out at around 1 to 2 pounds less then the other meat birds we got at the same time. It was two years ago we got about 8 or so as packing peanuts from McMurry's.
Turkey and chicks are not shipped at the same time from McMurry's there is any where from a few day to a week or more difference of when they are shipped because the use a different schedule to hatch Turkeys. But yes you can order them at the same time, but the minimums are separate.
For turkey's Great Whites and BB bronze usually go about 20 week for optimum Feed cost to weight ratio. 30 Weeks for Heritage types.
Great whites will be slightly larger the BB Bronze but the White meat is about the same.
But you can Butcher Early or later. We had one BB bronze female that was really mean and we did her at 12 weeks. Because turkey's are usually slow cooked you have much more range of when you can butcher.
The check to see if a turkey is ready to butcher you get behind the turkey and reach around it an feel the Keel bone, if it protrudes then it's not ready, it it is flush with the chest then it's ready.
Tom