Cannot say where the take off and return are but another thing to consider is that you will most likely need an electric pump to push or pull the water forward.
My 8.0m bus had one fitted and have seen them fitted in other buses as well.
When I did bus to M'home conversion I left two of the 4 radiator units in place, one under the dash for demisting and the other down by the drivers feet.
Duct tape is like "the Force", it has a dark side, it has a light side and it holds the universe together. nothing screams poor workmanship more than wrinkles in Duct tape.