Hi John
Obviously with the caveats that I don't know your boat's set up, I don't know how accurate these figures are and that my boat was the first 275 so things might have changed as the series evolved, here are the figures that are in my owners manual.
STANDING RIGGING
CAP SHROUDS s/s 1x19 6 mm 9.65 m Key + Bottlescrew* 2
LOWER SHROUDS s/s 1x19 6 mm 4.95 m Key + Bottlescrew* 2
FORESTAY s/s 1x19 5 mm 10.15 m Fork + Bottlescrew* 1
BACKSTAY s/s 1x19 5 mm 9.96 m Ball + Bottlescrew* 1
STROPS/TRIANGLE PLATE s/s 1x19 5 mm 2.05 m Fork + Fork 2
*RIGGING SIZES WITH BOTTLESCREWS 2/3 OPEN
I hope this helps
James
Morning's Minion, Parker 275, No. 1