Ladder as Stall Bar

Okay. Before buying any courses, I'm gathering equipment.

 

So I decided I would use a ladder as my stall bar, by buying an extension ladder and hooking it to a pole in the park via tie down straps, as explained here:

https://www.gymnasticbodies.com/forum/topic/11662-ladder-as-stall-bars-substitute/.

Speaking of which, is that safe?

Anyways, I was thinking of buying either this:

http://www.homedepot.com/p/Werner-8-ft-Aluminum-D-Rung-Straight-Extension-Ladder-with-300-lb-Load-Capacity-Type-IA-Duty-Rating-D1508-1/203134220?cm_mmc=shopping-_-googleads-_-pla-_-203134220&ci_sku=203134220&ci_gpa=pla&ci_src=17588969&gclid=Cj0KEQjw7IWgBRCjv8Cv4vfC3ckBEiQAE7nvR9AFTBrg7PqJtNMXkWPa3MQJXWtDCDjaXw8ENhu-vKAaAmQe8P8HAQ

 

which is an 8 foot, aluminum ladder.

 

OR 

 

http://www.homedepot.com/p/Xtend-Climb-8-5-ft-Telescoping-Aluminum-Extension-Ladder-with-225-lb-Load-Capacity-Type-II-Duty-rating-750P: which is a telescoping ladder.

 

Do you think the telescoping ladder is any less stable? The only reason I was looking at the telescoping one, is because it's more portable, and I don't want to walk up the hill with an 8 foot ladder!

So, does anyone think the first one is better.

Is this idea even safe?

Thanks

Sorry for the long post.

I have the 760P telescoping ladder -- tied to a "power tower" (which is stabilized by piling weights on the back legs). I find this setup works for me so far for most of the exercises that would otherwise require a stall bar. I think that the biggest limitation -- probably also true for most ladders -- is that the length of the steps is less than shoulder width. Between the centers of the vertical poles is 16". [Diameter of the vertical poles 2".]