Yes you can trim them but you read what happened to LOC. The stocks got thicker so the nutrient up take did improve.

You are correct in saying it just became a de facto NFT type of system. Any system using a feed tray will less then 12" of root growth room (measured from end of net pot to bottom) will end up being a type of NFT anyway.

The big difference is an NFT system pumps the nutrients at the bottom of the tray so the roots need to s t r e t c h to find water. With a top feed like I use and the sprinkler system like you are talking about feed the root ball and not just the long roots hairs.

If you have problems with water back flow then you should trim them but if you don't then unless you need to don't trim them. I could be interesting if you trim a few and watch them for you next grow. You could get some insight to how well your system feeds that way too.