Thanks Simo--- just knew there was a bright a#rse out there--hahaha.  sort of all came back to me when that ratio thingo was mentioned --

Now, to clarify, the back and front guys -forget them,as they are the raising/lowering guys.dosen't matter what length they are.

Now, the side guys(2 of them) they have to be equal length so as when the mast goes up and down there is equal strain on these 2 guys ,keeping the mast perpendictular and safe in it's decent.

Thats where your stuff comes in -- we know the height,say 25feet, we know the distance out from the mast we would like ,say 25 feet. Now ,what we have to determine is a distance out from the mast base along the raising or sloping ground !. on raising ground it would be less than 25 feet and  more than 25 feet on falling away ground.

Thanks ,  Dumb bruce