You could get yourself a gauge that is around 18' long, has a straight end, and the reverse at an angle. This is what I have found to be and easy way to check my DW rigs going back to 89 when I bought my first one. I also have a fill up end for my compressor that makes it easy too.
Don't get the gauge/fill type with both ends angled. If you have small openings like I do on my Navistar dump truck, you cannot get the gauge into and check the back tire very easy. Then again, the small openings make it hard to get one's hand into the hole to remove the cap too.
I have never heard good things about any of the extenders since buying my first DW rig, thirty plus years ago!
Marty
