I would see about trying to get it to 35%, which will help slow the weight loss some.
You're looking at around a day 50 to 52 hatch with that temperature, so he should be coming out any day now, anyway.
For the egg that is losing too much, you can try taping an area on it to reduce weight loss. You don't want to tape more than 10% of the surface area of the egg, though.
However, I've found that excessive weight loss can also be a sign of an infertile egg.