Draw two parallel timelines representing your professional and academic lives. What are you trying to accomplish at different stages of your life, and how will an extra degree support your development? Go one step further and define which school (or tier of school) you will be getting your MBA from. What job will you do post-MFE and pre-MBA to highlight traits that MBA schools care about? What story will you tell the MBA admissions?
Most quant fund managers don't have MBAs, and most MBA managers don't do quant trading. Most people go to MBA to change career or as part of their career advancement. You need to justify why your MFE and post-MFE career will be an unique addition to the MBA pool, and how everything will tie together after you graduate. Tons and tons of students want to become fund managers everyday, and you have applicants from all top hedge funds and asset management groups in banks. So it's only worthy to accept you into MBA if you're already an accomplished manager. But if your'e already a great manager, why can't you just hire another analyst instead of sacrificing your own income?
Make a great story about yourself beforehand, and turn it into a reality. By the time you write your MBA essays, you'll have much more interesting stories to tell.