Agreed, some adjustment in the cable will probably be required ..... Unless you are having a custom cable made
Sorry if you already know this Nick ..... The original Sierra pedal had a built in automatic cable adjuster built into it.
Once the standard cable is fitted to the Roadster all adjustment is lost & you start to fight the free length of the inner cable
Davids idea is a decent solution to cable adjustment
As Ash pointed out, The 1.3 Capri cable is ideal .... Just the right length, clevis pin eye on one end, ball fitting on the other + a decent adjustable section that will allow adjustment at the bell housing
Just thought this may help to get things clear in your mind mate