I am with NatGasPE - take the General Afternoon Section (I think they call it Other Disciplines these days). Its just more of the same stuff you did all morning long with an extra step to the problem. My reason behind this is - you already have your brain going a mile a minute with the basic concepts, don't try and change gears after lunch.
I took the FE twice, first time I failed and I took the Mechanical Afternoon because I have a degree in Mechanical Engineering, (duh!). Second time I took it, I passed and did the General Afternoon. When I think back to the first exam it was too much to try and do a four bar linkage question. It was easier to just do more math, economics and statics questions. YMMV.
The other advantage to this is, the yellow Lindeberg FE Review book, the FE Reference Book, calculator, pencil and scratch paper is all you need to study. I am convinced the only reason I passed the second time was I spent the better part of 8 months doing that Lindeberg book. Don't skip any chapters, go cover to cover. Understand every question. And by that I don't mean look at it for 10 seconds, realize you don't know it, glance at the solution, give it the nod and move to the next question. Really KNOW every question. If Lindeberg's solution doesn't instill confidence or you look at it and say "where the hell did he get that from?" then the internet is your friend as are your old text books. Research it and understand. Many of his solutions start from a shortcut method and he frequently does not start from the base equations in the FE Reference Manual and work the problem - he likes to show off and does his own thing. That's fine and all but *you* need to understand it. I have two binders of my own solutions to every problem in that book. I don't always agree with his methods but most of the time I agree with his answer.
When I took the exam the second time I felt like I had seen every single question on that exam. Granted, I think some of Lindeberg's answers need to elaborate a bit more on some of the explanations and you need to memorize a few economics equations that aren't in the FE Reference Book - but by and large I felt it was simply a matter of putting in your time.
We have several people here at work who aren't degreed engineers but came up "through the ranks" so to speak. Many took my advice and have since passed. I am convinced that the specialty afternoon modules are for kids still in school who's 300 and 400 level classes are still fresh in their mind and do not have to study much. You still need to be familiar with the Reference Manual but conceptually its all logged into your short term memory. I think anyone out of college for more than a year (or never completed their Bachelor's Degree in a Engineering Discipline) should just go for the General (Other Disciplines) to minimize the pain and maximize your study time.