VTF gauge

mc hit it on the head. Any Gauge will do you just make a stand for it that puts it at the level of the record. Just place the stand at the platter's edge with the gauge on top. I would use a small block of wood planed down to thickness. If you do not have access to a hand plane just place a sheet of 100 grit sand paper on a flat surface like granite and rub the wood back and forth till you get the right thickness. You could also cut card board squares out and glue them together until you get the right thickness.

Unfortunately, the Shure is no longer accurate enough. Most cartridges now come with a specific recommended tracking force which put the cantilever in the optimum position. The recommended VTF in many cases comes down to hundredths of a gram certainly tenths. An accurate counter balance scale would be impractical. An accurate digital gauge can let you dial it right in. I would be worried about the Riverstone gauge. It is very inexpensive. I would use some calibrated weights to check it's accuracy. The best gauges are 75 to 100 dollars. Even so I always take a calibrated 2 gram weight to check the gauges accuracy every time I use it.  These are a whopping 6 dollars!    https://www.amazon.com/Hestya-Calibration-Digital-Balance-Tweezer/dp/B078Q3JZY7?ref_=s9_apbd_otopr_hd_bw_b5Reiup&pf_rd_r=3MSYHZRTRFQWRVR5CDBC&pf_rd_p=37e1cdac-2bef-5b2f-9157-f1a14bd6

Forget about specs. Many of these gauges are 2-3 tenths off. Get that calibrated set of weights for $6. Trust but verify.

Good for you nandric. Many people do not. They assume their new gauge is accurate. Uberwaltz also checks his gauge. As for whether or not you have to check the VTF at exactly platter height dependson the geometry of the arm particularly what plane the vertical bearings are in. Ideally they should be at the level of the record.