There is something you have to consider about RG-6, though -- it is usually designed with RF above 50 mHz in mind, and often designed for cable TV applications.
Cable TV applications need a strong cable, and cable TV does not go below 50 mHz, so a popular cable is CCS, meaning copper-clad steel.
The RF signals travel on the copper outside of the cable because of the skin effect, and the steel core offers strength and stretch resistance to the cable. RGBHV signals, though, consist of signals from 60 Hz (sync signals) up through something like 65 mHz. Some of the low frequency signal will go through the steel, some through the copper, and the higher the frequency, the more will go through the copper.
Electricity does not travel at the same rate through copper and steel, so the different portions of the signal will not arrive at the other end with exactly the same time relationship they started with. This is probably not visible for runs under a hundred feet, but it might be. Why use a cable with a known flaw (for this application) and hope that the length might not show it?
RG-6 is available with a solid copper core, but you have to ask for it. Some wire suppliers do not know it exists. That solves the above problem, though.
The shield of RG-6 is always aluminum, in my experience, and is designed to take a crimp-on connector. Aluminum is slightly higher in resistance than copper, so it will attenuate the signal more than a copper shield would.
Until several companies recently introduced crimp-on RCA and BNC connectors for RG-6, the only connector you could put on it was an F connector. (Since the shield is aluminum, you cannot solder on an RCA.) Then you had to use an adaptor from the F to the RCA or BNC. My first experience with RG-6 used for RGBHV was to fix a missing color, caused by a poor connection through the adaptor. Replacing the adaptor fixed the problem. Until now, or some other random time. Better to used a connector with no adaptor...better to use a cable with copper shield to solder to, or use a crimp-on connector of the right type.
RG-59 comes with aluminum shield, too, if you search for RG59 for antenna use, but it is pretty rare nowadays. Usually it has a copper center conductor and copper shield. This is better than aluminum, resistance-wise, and you can always solder a connector to it if you do not have crimp-ons.
As for frequency response, I have built three retail TV antenna distribution systems with more than 450 TVs each, and the last twenty feet or so of each run was RG-59. Why? Because even up above 400 mHz, there is very little attenuation in such a short run of RG-59. For video, where we are talking 65 mHz or so, 100 foot runs of RG-59 are just fine. (I still will use RG-59 if we have it for FM antennas, which carry signals around 100 mHz.)
The mini-RG-59 is really a misnomer; it is mini 75-ohm cable. It can't be mini RG-59 any more than a teacup poodle is a mini wolf, because one of the definitions of RG-59 is its outside diameter. Another is its inside conductor gauge. A vendor I buy from calls this mine 75 ohm cable, but some of their products use RG-174, and it is also good for video. The thing you have to watch out for is how long the run is, which translates to how much the video is attenuated. Remember, white is created in RGBHV by having the R,G and B at their full voltage value. As the voltage decreases, your whites (Contrast or Picture) fade. You can compensate for this, but few of us have the technical equipment to properly compensate for an effect that we cannot measure. Buy RG-59 instead for long runs.
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