Thanks everyone for all of the great feedback! Much appreciated.
My scores thus far:
580 on my diagnostic (Q36, V33) (GMATPrep CAT 1)
650 (Q39, V39) on the most recent exam I took about three weeks ago. (MGMAT CAT)
I've been consistently logging between 8-12 hours of studying per week, and am aiming to score in the low 700's (720, 730).
I'm planning on taking another MGMAT CAT on Friday and hope to show some serious improvement...depending on how that goes I'll see if I need to focus more on stamina-building/exam-taking or my conceptual weaknesses for the remaining days...
Will keep you all posted! Thanks again!