1. At 1m length do the differences that may be present at longer lengths of say 2.5m become less noticeable?
Obviously the shorter the cable the less resistance, but there is plenty more to a speaker cables function than resistance.
If you agree with Transparent cable's philosophy every length needs its own specific network box to adjust capacitance, inductance etc. for maximizing sound quality:
"The balance of a cable's electrical properties changes according to the length of the cable. Transparent not only optimizes for the cable design itself, it optimizes every network for every length of cable to meet that specific product's design criteria. Regardless of the length of cable required for a particular system layout, the performance will meet the standard for that cable design. With Transparent, there are no compromises for needing a longer or shorter cable."
Their stock cables start at 8 feet, but they do make custom lengths. Not sure what they say if someone wanted to order some 3 foot speaker cables for monoblocks, I am sure someone must have them, or do they suggest only longer lengths are possible? Of course these may be beyond your budget.