rear suspension design help needed

[wedged]

I made a quick 2d overhead view cad drawing. O-O of the rails at 30.0", upper links mounted 6" apart on rear. I came up with 58 degrees included angle with an effective length of 18" for the uppers. Using the 70%-100% idea, the lower links would be 26" or less. I forgot to dimension the actual length of the uppers.

If i kept the frame rails wider in front of the tires, or had a crossmember in directly in front of the tires, I could make the upper links longer.

I'm going to fiddle around with the drawing and see what i can come up with.