... keep in mind that CPL training is around 37-45 hours of flying, whilst the requirements to undertake the exam is a minimum of 200h.
I don't think this is correct. You simply need the minimum 70 PIC time and total time of 150 to take the CPL test. The 200 hour figure is the minimum for CPL 'issue'. Most people do the MEP and IR and then apply for CPL issue at the end of the training.
As funkydreadlocks says, don't waste AVGAS burning holes in the skies, but I don't agree that you should make sure every flight counts in a 'training' sense. Have FUN! Take your family and friends for flights.
But like all things, a balance between fun and purpose is important. The CPL is not difficult and if you've done a bit of beacon bashing during your hour-building you'll be fine. The IR is the hard part because of the multi-tasking and your hour-building won't be of much help with that, but if you bear that your ultimate aim is to be a commercial pilot, so use your time wisely.