Coolant leak.. can't find the culprit. Please help!

I had a similar idea to wrap each hose end with a little strip of shop towel and secure with string or something... each hose individually wrapped. After a good drive get in there to see which one is wet if any. However it's so tight in there I'd be afraid the paper towel trick would be a fair amount of effort with inconclusive results.

 

I'm pretty sure the large hose was the culprit. You know when you slide back the clamp the hose is still supposed to be bonded to the pipe not just slide right off with ease. I cleaned it up and swabbed a coat of gasket sealant inside the hose and put it back on. I'm also going to order a new hose.

 

Anything worth doing... I moved inverter to the side and re-did it, applying sealant to the barb end. I also removed the dried clump of sealant from the inside of the hose.

Here's the efforts of mounting a goPro2 back there near the brake accumulator/fuel line. I don't think I should have used a flashlight it wrecked the contrast but you can definitely see something leaking.

 

I've tried resealing the big hose, and the medium hose (to CCV) twice. It still continues to leak from somewhere. I'm starting to wonder if the head is cracked or something.

 

Could it be something as simple as the brass washer under the coolant temp sensor? I swapped it out for a Honda oil drain bolt washer it seems to be a great fit. Like the brass one is so small in the outer diameter if it's not perfectly centered/aligned it would seems barely big enough to cover the threaded hole in the head.

Razor blade in photo for size reference.

 

Update: I actually picked up another 2007 about a month ago for cheap (cat cut out of it and no brakes). I stole the two hoses from it and put it onto my daily 2007. I also swapped out that brass sensor washer with an oil bolt compression washer. I took it on two 15 mile drives and it does not appear to be leaking. Oh and also I should mention I ditched the gasket maker goo and completely cleaned up the tubes coming out of the head and inside of the hoses and swabbed them with brake clean to make sure there was no coolant or oily residue on the mating surfaces.

I have ordered brand new "Radiator Inlet Hose" (Big hose) and Water Bypass Hose #3 (Medium hose) but those can take weeks to arrive. For now I put the possibly problematic daily 2007 prius hoses onto the new fixer-upper 2007 - I'll test drive it today to see if it leaks.

Edit/update: fixer-upper 2007 with daily's possible problematic hoses didn't seem to leak a drop on 13 mile test drive. I'm really thinking my leak was from the coolant temp sensor all along.

 

Update:

Brand new water bypass hose #3 (medium diameter hose from ICE Head to CCV) installed. Somehow coolant is still ending up on top of the transmission.

For comparison sake my other 2007 now has the hoses from my daily 2007 and it doesn't leak at all.