A mechanical gauge fitting would certainly be smaller than an electric sender, and will provide an accurate reading.
but will be a true PITA if you ever need to remove the gauge or the console for a project.
and if you get a brain-dead shop boy tasked with removing the console gauge panel, this is what you can wind up with -
apparently, he found removal of the capillary tube fitting to be too difficult, and so he proceeded to explore this alternative removal method.
The same brain-dead shop boy also thought this would be a good way to remove the AC thermostat
yes, this was all done at a shop that touts their Pantera experience.
Larry