Total solution: Under sink pop-up ball rod too short

Firstly, the pop-up assembly can be beautiful if you use expensive copper pipes or aluminium tubes, and maybe spray paint it too.  I use left over pvc pipes so it cost nothing and earn from freed storage space.

The old short horizontal pop-up ball rod is still there.  I extend the length by putting a 1/2" cpvc tube on the outside of it.  For my case there is not enough space to put the cpvc tube without cutting it in two half first.  So I use a cpvc coupler to join it again after they are in position.  I have to do that because if I don't have access to the ball rod when I screw the ball in, I can't get the rod through the stopper hole.

To reduce play (side way movement) between the old ball rod and the cpvc tube, I put in between them a 5/8" tubing, the thicker version for fridge ice maker.  The OD, outer diameter of the rod is usually 1/4", same as majority of tubes for fridge ice maker.  The next size tubing has ID, internal diameter, of 1/4", with OD 5/8" (I think).  Therefore the thinner tubes can be inserted into the thicker ones.  The tubing also prevents the outer rod from sliding horizontally.  If you need to you can add glue to fix the outer cpvc tube.

The horizontal pop-up ball rod is connected to the vertical pull rod by a 3/4" pvc tee piece as shown.  That's the next size pipe that allows the horizontal rod (tube) to go through while allowing some play.

The tee piece is fixed to the vertical pull rod via a short vertical pvc pipe section.  The vertical pull rod is universally connected to a flat bar with holes in it.  A simple screw will fix the pvc pipe onto the bar securely.  First I drill through the pipe with a plastic bit.  I use a long precise dry wall screw to nail the pipe and bar together.  It's better to use nut and bolt.

For the horizontal rod you can also use 1/2" emt pipes for conduits.  It's cheaper and can be easily cut using the cheapest copper pipe cutters.  CPVC was phased out already.  I just had some in the garage.