Best bread for grilled panini?
Different types of bread will make different sandwiches, none of which is inherently better than the other. For example any sliced rye would make a good Ruben style sandwich in the machine. Or plain white bread for the classic grilled cheese. For simple lunch use, I prefer a firm multigrain bread. The rolls you mention would fit Italian style ingredients. The French rolls would also work for a Mexican style torta sandwich (even better, a Mexican tellera roll).
I purchase a "white sourdough" from a local bakery sliced on the thinner side- brushed with s slight bit of butter...YUM. My favorite sandwich so far since I have started doing panini- grilled eggplant/shredded mozzarella, thin slices yellow pepper/ spinach, with a very light mayo mustard on the bread, kosher salt. YUM!