Depends the led strip. If the " bead on ribbon tape"? These usually are very effective under the FRONT lip of the upper cabinet, no channel necessary. With very effective lighting results on the counter. Unseen even when sitting.

The easiest thing to do might be to buy linkable undercabinet lights such as the GE-Premium Linkable Light Fixture:

• Length: 12 inch / 18 inch / 36 inch
• Length: 24 inch

These are a shallow 3/4" thick so you could just attach them to the undersides of the cabinets behind the lip where they would not be visible. You could link several lights together so only one light would have to be attached to an electrical box.

These are plug-in lights but you can use the Direct Wire Linkable Fixture Junction Converter Box to direct-wire a light.

We got this channel and it is awesome! It comes with a diffuser and clips that make it easy to install along the light rail. Look for something like this and I think you'll find the install goes easier and it angles in the right direction, too. https://www.amazon.com/gp/product/B00F9RTII4/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

The rail makes sense if you are using LED tape lights because its diffuser prevents the countertop LED reflections that can occur with tape lights alone. Tape lights, though, are low voltage and require a power supply. However you can make a really long run of tape lights; the GE undercabinets lights -- and other like them -- have to be installed individually and then linked together but don't require an external power supply.