Frame Rail guide?

[Tamiyaken]

First of all, you have to get the components that you need to fit to the rails and then you will see where they go.

For example, (this is how I scratch build some of my stuff) get the suspension springs and line up the location holes where you want them to be. Drill and locate them in this position. I agree it's handy to have a spare Tamiya set of rails but even these can be used to locate the axle spring positions, but other stuff will need separate locations.

Hope this helps

ken