I would like to put in my 35 Chevy Coupe Trunk 2 gas / mechanical struts. Not being a big math person. How do I determine where to put them and what sizes and clip attachments to get. I used a bathroom scale with a 2x4 to determine the weight it will take in the middle of the trunk to be 45 lbs. That at this point is all I know what to do. Please advise.