Several factors are involved in the window sticking phenomenon. One is the accumulation of salt and dirt in the channel.
Dock spiders build nests in the channel drainage grooves and one must direct a power water spray upward thru the drain slots from underneath. Lots of debris is flushed upward.
The vibrations from engines compacts salt, sand and dust.
Avoid any lubricant that is sticky or wet. Only use Dry Lubricant Spray with Teflon (ptfe).
Once the window is stuck, a vertical lifting motion is the easiest way to open it. I used one of those folding, blue, emergency knives from West Marine, and wedged it sideways so I could lift the front of the window while rotating the 5/8 inch thick handle up and aft against the forward window channel. Just the slightest upward lift while pushing aft will release the confining debris and the window will slide.
I tried all the expensive sprays mentioned, including the Boeing lube, but the only long term answer avoids silicone, grease, oil, etc. Any wet lube will attract and hold dust. Only Dry Lube with Teflon will work.
Routinely spraying out the debris from below, thru the drain slots, will prevent problems.