Hard to say what they'll do for you without knowing the condition of the bowling balls, how you bowl, and where you're planning to use these on.
Being very general, the Ultimate should roll earlier, and set in the pocket, where the Smash/R will be a little more continuous on the backend due to the Medium RG core and PK18 Pearl-ish cover.
If you're not drilling the balls yourself, leave the details up to the ball driller. He or she will be able to figure out if they can make the ball legal or not.
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Nick Smith ... A.K.A. Les Badderâ„¢
Brunswick -=- PBA 03-05
¡Viva la nación de Brunswick!