and was wondering if anyone had any suggestions of the most cost effective way of doing this
Look at it logically, you need 200 hours to qualify for a CPL and 150 hours to start the training. What are you going to do after that? Probably obtain an IR, so by the time you have finished you'll have 250 hours plus. Why not do the IR as part of the hour building, that way you get quality training from square one, rather than flying around in circles just counting hours. You need 50 hours cross country time to start the IR Course and then get a 10 hour credit towards the CPL. It is possible to do all of the training in a little over 200 hours thereby saving time and money. A PPL with an IR is of more use than a CPL without one.