The multiply, align and distribute tools will not help you adjust the truss sizes.
They will just help you arrange the trusses to the correct position.
Each truss that is a different size will need to be a new truss.
Or use an object that allows you to change the size and shape - maybe the one SenecaDesignLLC is suggesting? (I have not tried it but it looks interesting).
Still each different size truss looks like it will have to be a new separate object that you can adjust the size/shape of.
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