24G,
It sounds to me like you have pretty much made up your mind about taking a jet transition course. There is nothing wrong with that, if you have the cash laying around. It may help to build your confidence during the interview process, and during initial training. I also get the feeling that you are not a 250 hour wiz-kid, looking for the first shiny jet job you can find. If that's the case, take some time (within reason, we all know that seniority rules) and do your homework. Figure out where you really want to work. What equipment are they flying? What do their HR people say? What does their training department say?
Eagle told me, point blank I should go to ATP, and take a CRJ course. I simply wasn't willing to borrow eight grand to "maybe" get a $20K/yr job. (Would I pay for a B737 type after being offerd a position at SWA...hell yes)
At Express Jet the concensus seemed to be; "With your time, why the hell would you spend $8K, on something like that, when we are going to teach you anyway?"
If you do decide to take one of those courses, try to find one that makes sense. There are a lot of them out there. Choose, only after you have a pretty good idea that it will help you get, and train, for a job someplace that you really want to work. I wouldn't suggest a CRJ course, right before starting EMB-120 school. The primacy, and negative transfer of learning might hurt as much as it helps.
I am a new FO, and was a Gold Seal CFI, with over 1500 hours of dual given, when I started training on the ERJ-145. However, I had never flown anything faster than a C-310, and had very little instrument time. I'll be honest with you, training was tough for me. During training, I found myself wishing I had some previous sim time, in a jet, so I know where you are coming from. What I really needed was more varied flying experience.
Now, I feel like the CFI experience helped me more than any "train before you train" kind of program ever would have. I hear this again and again from the Captains I fly with, as well. I am also damn glad that I am not another $8K in debt on first year FO pay.
Just my two cents. Your milage may vary.