Your quiet right Bfit, good cables as short as possible, good ends (I solder/crimp mine), earth right to the SM mounting bolt.
Older style SM's will oval out the nose bush, cold start fine, but with heat/expansion they bind and struggle when the donk is hot.
Reduction gear starters are smaller, lighter, use less power, spin up the engine with a vengence.
Being smaller, by default, you may get better manifold clearance.
If possible fit highly polished, thin Stainless Steel heat shield, in preference to lagging or coats.
Spray the battery terminals with "Lanolin spray" - VERY very light coat after fitting terminals.
Only on the posts, the battery top should be clean and dry.
Hope some of this helps.
Oh, I've used fine wire welding lead for the major + and - leads.