Light transmission of polarizing filter?

[OzStarGazer]

I bought a GSO polarizing filter some time ago, and it works fine both during the day and at night, but I was thinking that maybe a ND filter with 25% light transmission would be a good addition because the sharpness with a polarizing filter is not ideal, particularly for astrophotography, while I have read it is much better with a ND filter.
What do you think? And do you know what the light transmission of the GSO polarizing filter is?
Maybe I should have bought two polarizing filters to adjust the amount of light, but I guess the sharpness would still have suffered?

[astro744]

I have a Meade variable polarising filter and when used for the Moon, small craters simply disappear! The resolution loss is noticeable and I simply do not use this (or any) filter for the Moon any more.

I'm not sure if all polarising filters behave this way.

[OzStarGazer]

Thanks, astro. Maybe I will give the ND filter a go after all... But with 25% light transmission because less than that will also blur the image (I think).
ND filters are not very expensive and people who have used both polarizing and ND filters think the resolution of the ND filters is higher. I think that polarizing filters are mostly designed for daytime use, although they can also be used at night. It is just that the resolution is affected too much at night.
PS: Unfortunately without a filter the moon is too bright sometimes, particularly when it is close to full.