I have three comments.
1. Where are you going to send the output from your skimmer? You'd probably want to empty into the second section. If it outputs into the first there is a chance some of that water which might go thorough the skimmer twice unncessarily.
2. By funnelling both drains into the same pipe before it gets into the sump you are likely to slow down the flow into the sump. Why don't you run both hoses into the sump seperately?
3. One of the reasons for baffles is to keep micro bubbles from flowing into the return section where they can be sent back into the tank. Your baffle setup may not prevent this. In the current setup there doesn't seem to be a need for the two smaller baffles. The bubbles are going to flow right over the top of the second section and into the return area. What you want to do is have three baffles seperating the return section from the others. Each baffle should be the same size and the middle of the three should be raised about an inch off the tank bottom to allow the water fo
flow under it. The water should flow over the first, under the second and over the third baffle.
Here is a link to some info and designs:
Other than that the design looks good. Are you going to put anything in the second section, LR
, or anything?