At the exposure times and distance that you're dealing with here you may find that you need only worry about stopping down to achieve desired DOF. You might also experiment with an 80a or 80b which will reduce the light by 1-2 stops, nutralize some of the manmade light and remove a bit of the red. It may not be an improvement as I like the red, but it is fun to play.
Thanks for the input JD definitely something to consider. I have two more 30 minute exposures from this outing and I didn't want any people in the shots but there were people everywhere. So I just figured I would make them real long and the people won't show up. And they didn't, pretty cool. Filters for this camera are hard to come by so I am trying to rig something to work. It is my play camera and it has been fun so far.