914 engine conversion: water-cooled hose specs, Engine-to-radiator and water-air intercooler hoses Options

[strawman]

I've searched but can't seem to find definitive answers about what size and specs for the coolant hoses for my turbo Subaru engined conversion. I'm interested in real world experience from others that have running water-cooled conversions. Based on my research of this site, I've decided to follow most conversion guys' use of rubber hoses in lieu of SS or aluminum pipes for the long run between the engine and radiator -- run in the recesses along the bottom of the chassis.

Renegade Hybrids sells Gates Green Stripe (or equivalent) hose, in 11' of 1-1/4" ID and 13' of 1" ID for -- including clamps -- for $100. According to their website, they recommend 1-1/4" I.D. from lower radiator to pump and 1" I.D. from upper radiator to the thermostat housing. Those sizes provided by Renegade would require that I use adaptors for both ends on each hose(engine and radiator), so I've searched the usual suspects like Ebay, NAPA, Rock Auto and marine suppliers for bulk heavy-duty 1-1/2" ID hoses -- but my head is spinning from all the options.

Is a "hardwall" rubber hose required (the type with wire reinforcement) for the engine-radiator hose? If so, marine exhaust hose seems to sell for ~$5.00 to $8.00 per foot on Ebay. It seems like the suction side should be beefier so that it doesn't collapse when hot, but maybe that is not important, so a two-ply polyester-reinforced hose might suffice. Any opinions from you Chevy V8, Subaru or other guys?

I'm also looking for 25' of 3/4" ID heater hose for my water-air intercooler setup, as my heat exchanger is mounted in front of the radiator. Again, is hardwall rubber hose required, or would any high-quality two-ply polyester-reinforced hose work?

Thanks for your opinions!

Geoff