Touring - Trekking bars and shifters

Hello all,
I'm new to touring and decided to switch to a trekking bar and have a question, how do you decide where to place the brakes/ shifters? Some people have placed the shifters at the top and others have them at the bottom? What do I need to know to make a decision? If you have pictures, could you share them to show the different options for setting up the bars?

Thanks everyone!!

I am in the middle of doing this myself. What I am doing is putting on reverse bar end levers and interrupter levers. Both the reverse levers and the interrupters are road levers so I also got travel agents to increase the pull. I'll post finished pictures tomorrow.

The bars will look like this..
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I had them up above on my old bike and down below on my new bike - both were fine. It'll take all of about 30 minutes to get used to whichever position you put them in. The advantage of putting them below is that it frees up more real estate on the handlebar for a computer/bell/whatever. As far as ease of use - they're equal.

Hear is a pic of the ones I had on my last Tourer,
These are Nashbar Trekking Bars, I slid the shifters and levers over the open ends and then inserted a piece of 1/2"EMT between the ends of the bar, then held the emt in place by its slightly tapered ends and then heat shrink tubing,
This got me more room to hang more accessories.
These bars are the only part of the old bike I miss.
I need to add, I originally had them on the other way, then I changed the stem and did this, loved it. All kinds of places to put my hands.

I grabbed some ITM butterfly bars before they went off the market.
Grip shifter: Rohloff, Brakes: Magura,,hydraulic, rim.
http://www.cyclofiend.com/working/2008/wb092-robertclark1008.html

I got the bars remounted, here are some current pictures..
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Like I said, because the levers I am using are road levers I had to use "Travel Agents" from 'Problem Solvers' to increase the cable pull travel. Here is a picture of the front Travel Agent mounted on the fork brake boss.
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If you do decide to use multiple levers and/or travel agents be sure to get tandem inner cables. The extra levers and the agents both increase the length of cable required and in this experience standard length cables were a few inches short.

Thanks everyone!! Can't wait to try it out.

I use regular mtb levers at the bar end,and thumbies next to the stem. Nothing complicated, everything is handy withi reach.

https://lh6.googleusercontent.com/-cY0OE1eaJDs/TYdn7s9EfSI/AAAAAAAABXA/mFcNq3P7dg4/s1600/031811205921_01.jpg

The carbon barends may look a little odd, but they are great palm rests when you want to sit upright and reverse stretch. All the junk and foam grips are down at the bottom, and that's where my hands are for railroad tracks, navigating through traffic, bad road..etc. I've had it this way for a few years, perfect. I wouldn't do the Brooks bartape again, it gets a little slimy when it's real hot and offers almost no cushion, but it's decent feel on bare hands.