Something serious as confined space is never a self-learn, it is always a class by certified instructors.
Depending on how many in the crew to do the job, if anyone has this type of training, who will be the competent person, etc....lots and lots of things to think about.
Way too much stuff to type here about the training, ongoing work, etc....
Jay, pm me or give me a call and I will talk to you about it or you can call Guy B, he also has a ton of experience in confined space.
Figure that you will probably have a hole watch, bottle person (both are dedicated jobs, they don't do anything else and do not leave their post without having someone relieve them that is also trained and certified in that job), few guys in the tank working, a person to watch over the site continuously (not leaving to go do other jobs) the size of the crew can easily be from 6 to 12 guys depending on the size and scope of the job.
Things this serious are taken very serious and if you accidentally mess up or someone leaves their post and someone sees that, you and your crew are usually escorted off site to not return as that company or corp can get in serious trouble with OSHA besides you for allowing your company to be slack in your proceduress.
You have to call around and see who in your area provides this type of training and certification, see how many days it will be for your whole crew and how much it will cost you (not only for the class and certification but you are paying your people hourly or salary to sit there in class for days for this while on the clock).
Feel free to give me or Guy B. a call and we can talk to you about this stuff.