It may not be ultra-precise, but cheap mock-ups can be very helpful, in my opinion. Below are some photos of a foamcore mock-up I did with respect to my rear suspension design. I'm a very visual person, and I wanted to develop a sense of how much difference change is my 4-link distances would make in practice. Materials-wise, it probably cost me $10 U.S. to make this.
I was trying to understand issues like bump steer and the danger of collision between the links and my axle housing for various amounts of bump and droop. A similar model of the front suspension would require modeling both sides, as you want to determine the geometric location of the roll center and you really would want to vary the location of the two suspension sides together, but independent of each other.
If you have access to some basic drafting tools like a standard sized T-Square and table top with square edges (or a big sheet of plywood), you can do it. I did things full size as I didn't want scaling errors introduced. I found it very helpful. Staniforth's string model would be a good model to use for setting things up with a front suspension.
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Ruler-at-3-Inch-Bump.JPG
Cheers,