Sorry to hear about the damage to your new board.
Sounds like you are doing all the right things toward the repair.
Only thing to add is to open the vent plug (maybe remove it completely) so
gravity can pull more moisture out and there will be a flow of air into the core
to keep it from making a vacuum.
When you take your board out in the sun, again put the crack at the lowest point.
Install and tighten the vent plug so that as the board heats up in the sun it develops
some internal pressure from the expanding air inside.
This will help to expel all the moisutre inside the core of your board.
If it's still weeping water, do the "heating up in the sun" several times until no more water
Be sure to open the vent as soon as the temp starts to drop.
This uses the vent as a "one way" valve, ensuring that pressure develops as the board's core
heats up, and then releases the internal pressure/vacuum as the core cools off ensuring that
it does not simply keep pulling the same water back in.
When no more moisture comes out, do your repair in the evening as the board is cooling, with the
vent plug closed as this will "pull" your repair resin into the crack as the board cools down.
Hope this helps,