What worked well for me was starting with the dog and cat questions because those were things that really helped me in clinics/life that I was likely to retain. I actually started them back in feb or something like that (against my own advice) because that's when zuku started their cheap deals for subscriptions that went all the way to Dec. just getting the basic questions out of the way for things like ckd, cushing's, dm, hyperthyroidism, hcm (pretty much stuff that i already knew cold and wouldnt forget) made me feel better because it kept my study percentage higher than the national average so i wouldn't get antsy feeling behind. I just marked the minutia that seemed like "boards only" type of questions to review later. I worked on the equine questions while I was on my equine rotations and did the same.
Then I went back to the minutiae and started studying them in Sep. i then crammed the small ruminant, bovine, porcine, and exotics 2-3 weeks before boards (50% of it actually the last 2 days...) because cramming is what I do best, and I honestly don't care about retaining this crap. I care about exotics, but there's so few questions that it didn't take long to go through it. I'm someone who can't learn about topics I'm weak on unless I sit down for a long time and sort everything out in my head at once, so doing a few questions here and there for the food animal stuff would have been futile.
I invested in 2 of the full length navle exams, and I thought they were worth it. I did one a month or two before boards (when I was done studying dog, cat, and horse), which was the best decision ever. It projected me to pass with pretty good margins, so then I felt comfortable not caring about any of the other subjects. In the end I completed zuku (at least the study mode, didnt do the quiz mode), but I never really felt stressed about it. It also helped me make the executive decisions to just not worry about the food animal toxins. The second exam was probably unnecessary, but I took it the day before, and it made me confident enough that I could sleep well. The tests really helped me get comfy with the format and timing of the exam, that I was able to zoom through using half the time given. It helped that the days prior to taking it, I was doing enough questions that it was like taking 3 navle's per sitting. It made the actual thing seem really short.
It really helps to have the pathology rotation before boards!