Transmission cooler install... adapting raw water hose size & odd sized hose barb...

[basssears]

Working on installing a raw water transmission cooler (really just a heat sink, but that's what's available for my Hurth HBW100-2R). This is the cooler: 3306107001 ZF Transmission/Gear Cooler

Two questions have come up for me:

1) The raw water in/out barbs on the cooler measure at 1 3/16" OD (which is an odd size but that's what my calipers said, possibly because of a slight imperfection in the casting of the barbs). Question here is should I use 1 1/4" ID hose and hope it clamps down tightly enough, or should I use 1 1/8" ID hose and hope I can get it onto the barb (maybe with help of a heat gun)? Was planning on using "soft" raw water hose (fabric reinforced but not wire reinforced) for this new run.

2) According to my engine manual I should be taking raw water off the circuit after the raw water pump and running it through the transmission cooler. This will involve two T's into 5/8" ID raw water hose (after raw water pump before heat exchanger)... those two T's are going to need to connect to hose that that will run to the 1 3/16" OD barbs on the cooler... so I am going to need to adapt up to larger hose in the run (i.e. T'ing 1 1/4" ID hose out of a 5/8" ID circuit). What is best practice for this? I see there are bushings for adapting DOWN in size but haven't seen an equivalent for moving up in size. Female to female adapter->bushing->male to male adapter? Hoping not to have 8 million connections in this system, being below the waterline and all...

As always, thanks in advance.

-- Bass