I've got rubber hatches now, but on my first boat I did the strip hatches. One thing I found that made my hatches much dryer was to trim the gasket to make it narrower. I trimmed 1/2" wide gasket material to make it 1/4" wide. (if you can find 1/4" wide gasket, all the better) I suppose it's counterintuitive, but regardless of the thickness, a wide gasket takes more force to compress. If your surfaces aren't perfect the high spots need to compress enough that you also have good contact in the lower spots. The narrower the gasket, the easier it compresses. Good luck.
Mark

: I'm a bit disappointed in my hatches - they're a tad shy of dry
: (actually several tads) and I'm unsure what I failed to do. I
: thought I'd followed Vaclavs' directions to the T - but the end
: result suggests otherwise. I'm wondering if the deck shape
: changed significantly , though I removed it, made the inner lip,
: and joined the halves again before the epoxy had fully cured.
: Perhaps thicker gasket would help - though finding 5/16 (I used
: 3/16 to make it, 1/4" to replace) has been challenging.

: I'm always willing to learn from the experts. Thanks.