Yes you can. If look at the placement of where the trigger is, it's at the bottom pole.
That's actually looks really good. Can you adjust the flow as well or is it just a turn on and off switch? I know there are times where my flow is too high and other times too low. I have a flow valve that helps, but sometimes it's a pain figuring out the flow for each site.
I don't recommend it for any pole over 25ft. That was also the recommendation from the cleaner I got it from. Anything over that and I go with an AquaDapter which is a on/off control tap. The loop of hose to the switch would be way to big and become a hazard. As for the flow if you have a pump box that regulates the flow from your pure water barrel. If you are coming right from your system you could use an adjustable tap at the end of your pole hose and reduce the flow there. However when it comes to wfp work you want a good amount of flow to get a good rinse for perfect results. Too little flow and you risk spotting due to not getting all the dirt off during the rinse.
Kris you may be confusing flow and pressure. Think of it in terms of pressure washing. low psi and high gpm are what you need to clean. With wfp it's the same pressure causes splashing that can bring contaminants onto the glass. But low pressure and high flow will get you great results.