I'm just in the middle of doing some but they're solid not flexi hose- in polished brass to go with the rest of the gold/brass bling bits I've got.
If you need the measurements the holes are 146mm apart centre to centre, the thread size is M14x1.25 which is 12mm deep into the cover and the 14 mm crush sealing washers are the same part numbers as the oil drain bolt.
Had to buy the die to cut the threads as it's not a common one found in tap and die sets, if you are using alloy fittings you should be able to get the M14 banjo bolts off the shelf at specialists.