If you get the Specialty Plastic ones, remember to order 4" for under CP mounting, or 3.5" for metal mounting.
The GGG ones have notches for doing either length.
I'm not sure exactly where the SlikStik ones fall height-wise.
They say they are 1/4" longer than the stock Happ ones, which I think is the measurement of the shaft below the bottom of the handle.
How the Balltop vs. original teardrop will affect the overall height, etc... is the part I'm not sure about.
As far as the cheapest replacement goes, that would fall to a set of NOS Wico handles.
The only issue is that the 3.5" ones will require a metal CP, top mounting, or a metal mounting plate to give you the proper height.