Help with PSU Power Traces (+/-12V, +5V)

[Caterpiggle]

Hi guys,

I've been working on a very simple power supply that provides 3 voltage rails. The +/-12V rails can pull 625mA each, and the +5V rail can pull 1.5A (2.75A at some points on the board). I've designed a PCB to allow for these currents, but I'm a bit worried since I don't know the standards for this sort of thing.

The large square on the bottom is a thermal pad for the large DC-DC converter that provides the +/-12V rails. The thermal pad is connected to the ground pour on the bottom, with thermal vias to pull heat towards that side.

The large traces are 2mm wide, and the smaller are 0.508mm. Some of the power traces I did by hand to provide more current (while still looking clean). Is this necessary, or possibly bad practice? Is there a better way to do this?

I'm also concerned about the ground paths for some of the connections on the bottom. They have to run across the whole board and take some long paths. I made sure to make the thermals thicker for higher current.

I appreciate any input or help you guys can provide.

Thanks!