Hello planning and mocking up a cob LED install for a cat walk up over my living room using some 24V COB leds.  After trying out a few different set ups have decided mounting black channels with black diffusers directly to the existing railing as a side mounted wall wash. This will end up a lot cleaner looking compared to my original plan of a surface mount on the trim (shoerail) under the railing. Less indirect light bouncing off the ceiling, but no visible LED channel from the main room, and no direct shadows from the railing being right above the LED.  I understand power requirements and the amount of brightness I am giving up with using a black diffuser, but having it blend into the existing railing structure is worth it and I am only using the lower quality mock up at 50% power so far. After a lot of research and some advice here on reddit, I've decided that the 24V cob is the way to go for my 34 ft and 12 ft runs and will be moving forward with ordering those along with a controller and power supply.  I am stuck on picking a channel type for this space as I only have experience with using the low profile U channels in non direct visible installs such as pantry lighting. Images of channel options with dimensions below as the links can't seem to be posted.

So **question #1** is how much of a difference does a V channel vs a low profile U channel make in regards to beam width on a 180° COB? Would having the strip angled 45 degrees allow for better diffusion of light on the wall / ceiling with less shadows,  or is the low profile U channel going to do a better job of allowing more of the 180° beam to wash the wall /ceiling.  I've seen comparisons online for different channels and diffusers for LEDs with 30, 60, and 144 per meter on what is a spotless install that were great, but nothing covering this specific question with a high led/m COB.  

The picture above is of the railing with a temporary white low profile U-channel 17mm x 8mm with another U channel behind it as that is the dimensions of most of the V channels are and I wanted to be sure that it would fit without protruding too much.  When doing the mock up at night (not pictured) I found the additional depth of the empty U channel behind the front one pushes that further out to help clear the top rounded hand rail. This seemed to help minimize hard shadows caused by the handrail blocking light on the ceiling which is desirable.  Not planning to double the channel but **question #2** is if I went with a deeper U channel such as the link below it would accomplish the same or am going to lose beam width from having the cob sitting further back an additional 6mm from the diffuser? In short do COB lights with a 180° beam preform better in a shallow U-Channel?  If that's the case I could look at sourcing a two step channel but those seem pretty expensive or just using another material to back the low profile channel. Apricate any thoughts on these questions.   

V Channel 

https://preview.redd.it/54po2jk850jh1.png?width=1500&format=png&auto=webp&s=495633b0846c88a11e03cf779920c935ede501f1



Low profile U-channel

https://preview.redd.it/f9fo143650jh1.png?width=1500&format=png&auto=webp&s=bb8b19b644366b884db68ad41306f62c072e6e1a



  
Deep U-channel 

https://preview.redd.it/qcfgerf050jh1.png?width=1500&format=png&auto=webp&s=5aa6b85cfb2f4473e53cc69bce680b477eb2dac9



   

  


LED light V channel, low profile U channel or deep U channel with diffusers for cob install