The role of an OT Prot Pally in TBC raids

Hello, I have a lot of questions for TBC regarding the role of protection paladins however I will try and just ask one so that I don't end up writing too long of an essay filled with scattered questions. As a protection paladin, meta would dictate that you will be off-tanking the majority of bosses in your raids. There are exceptions to this rule, but more times than not, the protection paladin will be tanking adds or trying to maintain second threat on a boss. We are the trash tanks, not the main tanks. When you are attempting to maintain second threat, are you supposed to throw on a two-handed weapon and try to maintain threat that way, or will you continue to use your shield and build threat? This may seem like a simple question but I have never played protection paladin but intend to during TBC and can't seem to find a solid answer. I have searched through YouTube and most of the videos found will be of people trying to show everyone that protection paladins can be main tanks, however I've read that this will simply cripple, or slow, your raids due to how slow a protection paladin can gain threat on a single target.

I would appreciate any insight, and if I am also barking up the wrong tree on any of the points I've made above, please correct me as I am simply here seeking more knowledge and would love any input.