Berger is the only manufacturer that publishes all the data required to make a good selection. See this Quick Reference Sheet, to get a handle on what each bullet requires for twist. You might be able to shoot those that are listed as a 1 in 9", as Berger rounds there recommendation to the next full inch. Try their Twist Rate Calculator to get a more exact recommendation on each of their bullets (from the drop down box), while entering your specific twist, temperature, elevation, and muzzle velocity. You can also check other manufacturers bullets if you have the BC and overall length. This bullet length database may be helpful with length.
The 75 grain V-Max is probably OK, but not the 100 grain unless it is a flat base.
For what it is worth, the most accurate .243 bullet I have found for my 12 twist 6BR is the Berger 68 grain Target Flat Base, over 34 grains of Varget, and a BR4 primer.



























