.... I am not going into uranium mines or anything like that.

I see you have your location listed as New Mexico. I have a unit there but until the person that is hosting the station in their house returns home for the Fall to reset it, it is inactive.

A Geiger counter measures counts per minute. That's it. Counts don't convey energy info, or even the type of radiation (e.g. alpha/beta/gamma). The unit mR/h is a measure of absorbed energy dose rate of radiation. So it is impossible for a Geiger counter to measure mR/h directly. Converting from counts per minute to dose rate is something akin to voodoo math. You have to make a lot of assumptions about the probe and the isotope (e.g. Cs-137 is a popular calibration standard) you are measuring. Change the probe and the conversion factor goes out the window. Change the isotope and the conversion factor changes too (although energy compensated probes try to get around that.)

The mR/h scale on the CDV-700 was intended to be used with the hot dog probe and the beta window closed. It gives an estimate of how much gamma radiation the probe is exposed to, but only under those conditions. If you open the beta window, those conditions don't apply any more, so the mR/h scale is useless. Only the CPM scale has meaning. The same is true with the pancake probe.

The pancake probe is extremely useful to detect pure alpha sources. The hot dog probe can't detect alpha at all; the thin metal of the tube is enough to stop alpha. Pancake probes have thin mica windows to allow alpha through.

Beta radiation is stopped by metal. The hot dog probe has shielding to block all beta. Opening the shield exposes the tube, but the metal wall of the tube blocks some beta. Because the pancake probe has a thin mica window, it will be more sensitive to beta than the hot dog probe with the beta window open.

It is also useful to note that Geiger tubes are extremely insensitive to gamma; only a small fraction of the gammas entering the probe result in a count. Overall, gamma sensitivity is orders of magnitude lower than beta sensitivity, assuming the probe isn't shielded against beta.

That said, use the right tool for the right job. If you are being exposed to gamma, use the hot dog probe with the shield closed, and because it is energy compensated, the mR/h should be about right. If you want to look for low levels of contamination, you probably want to look for beta. Cs-137 emits comparable numbers of beta and gamma. But because gamma counting efficiency is low, you will do a better job looking for beta, and for that, the pancake probe comes in very handy. I've used the pancake probe to detect low level Cs-137 contamination on clothing we wore in Chernobyl. The hot dog probe in gamma mode detected nothing above background because of the low gamma counting efficiency. But the pancake probe homed in on it easily.

Great news.

Please keep me updated on your new toy (HIRO+plus K62) when you get it.