I had a 20-odd foot X-tel and I used it for one window before putting it back in the box.
Horribly whippy, almost bends 45 degrees.
Very heavy.
I wouldn't recommend one.
Fibreglass extender or superlite for me.
I used a 12ft extender as my main pole until i got a 17ft xtel. The extender was or is, a cracking pole as well for the price.
And andrew is right about info given on the basis of old poles. My 25ft is a 1 1/2 years old universal. And there have been so many pole innovations since then. The standard and choice now is much much better.
A flow controller is certainly a good thing to have if you want to conserve and have the cash. Although i have one 1, i run my van mount straight off a flojet pump most of the time now. And prefer it as i find it quicker to use a higher flow rate. I do have a plastic on/off valve between the tank and the pump which i use to adjust the flow to the pump.
Mr d, you say have 1k to spend. You are lucky that you can probably get yourself up a good set up with quality basics.
As suggested, getting the tank in the van done properly will be the most important single item. And getting the floor protected 1st will also make things easier for you.
You won't have to take your van out of action at a later date. A battery, pump, hose and pole are very quick to replace.
I notice many suppliers only sell shurflo pumps and not flojet. Maybe the deal isn't as profitable? I have had both for over 2 years and not had a problem with either.
But, whenever there have been pump problems posts on here, the vast majority seem to be with shurflo pumps.
Finally, if money is an issue, after a few cleans you will learn better what is required to suit your needs. I have 4 poles sitting in the shed that never really served their purpose from the beginning. But were the best of a limited option at the time.
You won't need to make that mistake, cos the choice is better.
A 17ft xtel or an extender will get you through until you have the cash to make a purchase that will last a few years.