How often would you say is necessary to do RT’s during the day? I read that 12 will work, but that doesn’t really seem like enough to me. Also, how thorough do you think RT’s should be? 
Well the correct answer is: enough to make it a habit 
You must balance it between doing them only on rare occasions and focusing on them all the time.
But the most important thing is to perform them correctly: not only doing some nifty tricks, but really questioning about surrounding reality.
The more you do them the more likely you’ll do them in a dream. if you can do it once an hour, that is great. If you can do it 3-4 times an hour, it is better. Just remember not to absent mindedly do them. It helps to mutter to yourself “Am I dreaming” before you do it to shake yourself out of the hazey half awake state alot of people are usually in when not having fun (Work, school, driving etc.) and after your reality checks you may want to mutter your results like “no, I am not dreaming” or " Yes I am dreaming" Just so you realize it. As far as how thorough I only do 3. The breathing test (close your nose and breath through it) The finger test (Count your fingers) and the can I see my nose test (Close 1 eye and see if you can see your nose). But it is up to you. Some people do 1 test, some people 6 or more. Some people like to do external tests (Like looking at text) but i find that those aren’t always readily available in dreams. Of course lucid dreaming is a personal experience and all people aproach them in different ways and respond to different things, So you need to find the right mixture for you. just don’t do RCs every 3 seconds. people will think your wierd 