You may need to improvise as I am. Sections of 5/8" and 7/8" hose, with brass 90deg. elbow and 7/8 <=> 5/8" reducing coupling. The 5/8" hose connects to the heater core, running downward to the elbow aiming frontward along the engine block, to another 5/8" hose piece running forward along the block, then the reducing coupling to 7/8" hose which fits the drain valve, and the 7/8" hose also for the short piece between the drain valve and thermostat flange.
7/8" coolant (heater) hose may be hard to find. Most my FLAPS did not have, but finally one did, after much calling around. Otherwise, as somebody suggested, a marine (boating) store might be a good bet.
I prefer metal elbows and adapter nipple over the plastic ones the FLAPS had, so found these at Lowes home improvement box store:
Attachment 1156 Attachment 1157
Hmmm, attaching photos not working correctly ATM, but they were brass PEX fittings, the PEX size 1" fits the 7/8" hose, and the 3/4" size fits the 5/8" hose. So a brass PEX 3/4" elbow and brass PEX 1" x 3/4" reducing coupling is what I found to work.
The other heater hose (connects to the rear of the engine block) has already been worked out, using a still available VW molded hose piece to an elbow to another section of 5/8" hose up to the heater core. Details and P/N
here: How To: D24T Heater Hose Replacement, On a Budget