Hello Jerry and List;
If I understand things correctly, you already have the cement base for the tower pored?  If so, probably the hardest part is done.  I know that is not much consolation but digging and poring the concrete can be work.
As for height although the higher the better has always been true, if you sacrifice five or ten feet and end up with with something that is more easily worked on you might be further ahead.
Many times you will only hear one side of a conversation on 20 meters and above.  I didn't find 40 & 75 to have that problem as often.
Not certain if radials are going to do much for receive.  They will help the swr which may help a bit and they will certainly prevent most of the rf from being absorbed when you transmit.
Richard