Somewhere on this site Marty has a link to the tide charts, otherwise just Google it for Belize. Personally I love to get out either just as the tide starts, either in or out, but that's for full days. When you get a chart you'll see there are 2 highs and 2lows each day. On a 1/2 day trip I'd look to get out 2hours before either high. You may find that a nite trip is best. "nite" is misleading'cuz it's usually 5pm-9pm. The point is, you want moving water, the faster the better, so check the variations for the days you may want to fish and pick the largest.

Flyfishing my way through mid-life crisis.