job's done.
no replies on my last post, so i just went for it. ended up getting 8' of 1/2" gates green stripe. after removing the heat shield and old lines (totally trashed...) i lost about a gallon of coolant.
I measured the length for both hoses and cut two lengths to fit. one line is slightly longer than the other. remember, the front nipple closest to the center of the truck runs to the rear-most nipple going into the rear heater core. this hose should be about 32". the inner one should be about 31". i used automotive heat tape ($20 from o'reilly's) to fasten both hoses together, making them a little easier to maneuver under there as one unit.
i hooked these up and used regular hose clamps up front (the front nipples didn't seem long enough for two clamps per hose) and i used double clamps in the back. i couldn't source the constant tension clamps and needed to do the job, so i just used regular clamps (hey, toyota just used generic spring clamps in the first place, so i'm going to check my OCD on this one.)
i routed the hoses along the upper part of the frame and used a combination of the heat tape and some heavy duty zip ties to fasten it securely to the frame rail. if i had to do it again i would probably use duct tape first and then cover that with the heat tape. the heat tape is expensive ($20 for 15') and sticks to itself well, but not much else. it didn't want to stick to the dirty cold metal of the frame, but i wrapped it around about four times and i think it's pretty secure.
one note, there is a flange back there that is attached to the frame for holding the O2 wiring harness in place. you can just bend this toward the center of the truck a little to create a space for the hoses to run underneath.
i ended up putting the heat shield back on, just for added protection. i also wrapped heat tape around the exposed portion of the hose coming from the upper rear heater lines, for a little added protection from heat generated by the cat.
tightened everything down, topped off the coolant and fired her up. i ran it for about 20 minutes, checking for leaks. all the hoses looked dry and leak-free, although there is a bunch of coolant stuck down in the cat from when i disconnected the old lines. i noticed some drips but i'm thinking its from that. both front and rear heat blew really hot.
i thought about sleeving the green stripe, but after looking at the setup i don't think it's necessary. the frame provides lot's of heat protection and if you fasten the hoses well there's just nowhere for them to rub. also, the green stripe is so burly i think it would take a lot of abuse before failing.
so all-in-all i have $28 in hose and clamps, $20 in heat tape, a few zip ties and $10 in coolant. not bad as opposed to $130 for the new OEM hard lines.
the job took about three hours start to finish, but i'm slow. i think using the hard lines would shave a good hour off this job, so that should be considered if you are going to tackle this job.