I recently bought a Ponderosa slant load, my first slant loading trailer.  I haven't used it yet, but am concerned about the way you have to secure the dividers.  It is simply dropping a pin through a hole.  Do these closures work alright for you, or is there something I can do to make it more convenient?  I know I may be whistling in the wind.

Yes, they work fine. 
However, hubby had a horse that bent the pin somehow and it's a B* to get it out!

My current trailer is like that.  I have a pin on a chain I drop in. 

If you are careful like you should be with everything, it will be fine. 

I got my finger smashed in it, so just be careful when you drop the pin in, I wasn't paying attenion and when I put the pin in, my mare backed up and hit the divider and pin and smashed it together, had to smack the you know what out of her to get her to relieve the "pressure" off the pin before I could get my finger out...  needless to say, good thing there were no kids around and my horse can't repeat the names I called her!!  :)