You mention using a spacer to provide enough droop. I was wondering how to get more slack (droop) when the cable has a fixed length. A spacer makes sense. I'll see how my new cable fits and if I need to fabricate a spacer.Always interesting on here.....
For what it is worth, here's a poor photo of a bog standard R8 clutch cable in place with normal droop. It's been like this forever and has no clutch shudder. My gearbox isn't as amazingly clean as BobG's but it has not been out of the car for at least 35-40 years and 200,000 km.
Another answer for BobG - the cable outer is not secured at the gearbox end, it just pulls out of the adjuster assembly. It's held in by the greater length of the outer relative to the distance from the fixed mounting point at the front and of course by the inner cable being secured to the clutch fork. So the engine/gearbox assembly can certainly move quite a bit on the rubber mounts without changing the clutch cable adjustment and, therefore, without causing shudder (not that there is not necessarily another contributing factor like the clutch itself). The easiest thing to play with is that cable droop with a spacer arrangement where it goes into the adjuster (which will then need adjusting of course). I have 2-3 mm free play.
I certainly make sure the two steel strengthening braces are in place and tight. Over-engineered for freeways perhaps but they were designed and built when many people drove on bad roads. There are several different geometries for the different engine versions. Heaven knows why as they are all Sierra engines, but the block mounting points changed over time.
I make sure all the cooling stuff is in place, and the car certainly is prone to over-cooling! Very efficient system and patented by Renault I think. I've never run it any other way but some obviously don't have problems without all the trays in place. Mine does get driven on 40-degree days sometimes.... It never overheats.
As to the gearbox braces, neither my R8 or R10 parts car had them. The R8 was from a stalled restoration project so it might have had them originally. I noticed my non-factory manual lists several versions of the 330 gearbox, some of which were designated "rough road." My R10 didn't have one of these. Maybe only cars with these gearboxes had the braces.
Bob