BC's steel lines are the safest bet. Less likely to blow out and drain all the oil out of the engine than rubber hoses, although hoses rated for hydraulic system pressure would be pretty safe. If the engine were disassembled, enlarging the tapping on the oil rail (rear one) would help with flow, but I wouldn't try to drill and tap that one larger with the engine together. I'd be afraid of getting metal chips into the engine bearings. Getting everything up to that point a bit bigger would probably be OK.
