Hi paul, had the same problem with mine (72 crossover). Very hard to go down pillars without cutting and drilling etc plus someone had welded over the outlets to the centre drains. I used a hose that fitted snug into the existing short plastic hoses at the front( about 10mm from homebase). I ran these to the back drains and teed to the plastic hose on the back then ran a hose through the outlet in the air intake and down to the floor/battery tray then through the floor so it drained out onto the ground. this pipe is small enough to feed over the roof braces behind the head lining and through the existing outlet where the air intake is. my middle drains have been blocked off at the mo, I may try to open up the original middle drain holes and sleeve some hose down them or T into the new plastic pipes later on. The T pieces I got from B&Q gardening dept ,they also had some larger hose that may fit over the metal part if you want to try another way. Hope some of this makes sense, trial and error really, much easier if your doing a resto and can remove the headlining als a good idea to fit some kind of seal around the sunroof itself to slow the entry of water down.
good luck which ever road you take cos they are a great thing when they work 8)
