Its a personal choice. Remember that the GCMS notes will take 30-45 days. Usually as per the existing trend right now, BGC is the last stage in the application process. Until a few weeks ago as soon as the applicant's BGC went in progress, within 1-2 weeks PPR came in. However, now it seems that the wait times have increased at this last step. This is for the Outland applicants.
For the inland applicants, the BGC goes in progress soon after the AoR and remains in progress until the application is closed.
So its your call. I applied for my first set of GCMS notes in January, since there was no movement on my file from October until I applied. I was happy to know that my eligibility had passed. The notes only help you see what has happened on your file and take some corrective action if there are any concerns.
Its all about personal preference. So if you think you want to apply for GCMS notes, go ahead. If you just want to wait, you can do that. And on the brighter side, what if you apply and receive a PPR before you get your notes