Hey Kenny-
I forgot there were pre-set buttons on them if that tells you anything. I have tried pre-heating, but I didn't notice much of an advantage. Part of the reason probably is that when you pre-heat, you have to open the door for a while to load the meat, thereby dropping the temp quite a bit. Further, if you plan on getting the wood smoking while pre-heating, opening that door while the smoke is chugging away is quite an experience.
I'd just try to find a time/temp combination that works for you for each type of meat that you want to cook. You can use the pre-sets as a starting point if you want. If you think your ribs needed a little longer, just set it manually, and add a little more time. If they are still a little tough, let em go another 45 minutes or so. You might even wanna make that only 30, since BBs are smaller ribs. I have only cooked spares on the Cookshacks, so your BB times may vary. For that matter, I don't know if the pre-sets are geared towards spares or baby-backs.
I'd just keep experimenting with out the pre-sets, and keep notes of what seems to work best.
Best of luck to you! You won't go hungry while you're testing!