I apologize up front for another post on merits/challenges of doing a HM prior to full marathon race. I read the previous thread and lots of good info to consider

My particulars:
I'm returning to steady running after a 3 year period of sporadic activity. Since March I've been building a base and am comfortable at 47 mpw right now. My goal marathon is Dallas White Rock on 9 December. I'm following the Pfitz 55/12 plan. This week I started the 8 weeks to goal schedule, so actually have an extra unscheduled training week I can work with before my marathon.

I'm considering running a 20K race this weekend. On my Pfitz plan, he calls for shorter tune up races 4 and 2 weeks out. However, I enjoy racing (at least apre race!) and after mostly running solo on long training runs, feel the need to run fast and get a race in. I'm curious to see how I've progressed as well.

Questions:
1) Is this 20K race idea 9 weeks out from what will be a serious BQ attempt ill advised? Pros and cons...
2) If I do the race, any recommendations for a training plan for week after the race.

Thanks!
Dave

Backgound:
I've run 1 Marathon (USMC in 2004, 3:23) and have set a goal of BQ'ing before I'm 40 (I'm a 39YO male, so 3:20 is my magic number). Earlier this summer I ran a 3K (11:50), 2 5Ks (21:23, 21:18), and a 5M (35:13). All the races were run in pretty hot and humid Dallas summer conditions.