What leafs to get for my 58 Burb?

[Mr Pops]

One of the previous owners removed all the leafs, I'm guessing so as to mock up a desired ride height. So the axles are both sitting on the frame in this picture.
For the front: I'm thinking I'll buy a drop axle (3" or 4"??) which will theoretically keep the front end sitting about the same height as it is now, while giving me a few inches of travel between the axle and the frame.
For the back: I'll probably hold off doing a notch in the frame for now, so I just want it to sit about 2 inches higher than it is now to give me a little bit of travel without going too high.
MY QUESTION: Since I don't have the stock leafs, I have no idea what to tell the spring shop to make. I'm sure I could measure from hanger to shackle and get a close enough leaf length, but I have no idea what spring rate to get, or what arc will give me what height..
I want this to be a LOW BUDGET build which is why I'm choosing leafs over a mustang II and a four link etc..