Have actually spent time with the 130mm F/5 Newtonian on the EQ-2 mount? I like to keep in mind that when I recommend something, people maybe spending their hard earned money, I like to be pretty careful in my recommendations, I like to have had experience with the scope or something very similar..
-I owned the Towa-Meade 80mm F/11 on that mount in the photo, it was undermounted but it was usable..
- The reflector is on an EQ-2 mount, it's basically the same scope as the SpaceProbe 130ST. As has been discussed previously, I owned one of these for a while. By my standards, it is under mounted. In my mind, under mounting means that the mount will limit the capabilities of the scope, it will vibrate and wobble, making precise focusing difficult or impossible, it will vibrate in a slight breeze. Stiffer legs are a help, I would recommend to Giovanni that he build or purchase some wooden legs.. It has been my experience that these mounts can be significantly improved significantly. With a Newtonian, they can be very short so they can be one piece.
Regarding that you wrote that "it was not ideal." This is what you wrote:
Equatorials are for more serious study, to better hone one's observing skills, without the less-capable mechanics, and if one prefers. Conversely, alt-azimuths are for casual observations, in flitting from one object to another; this one over here and that one over there, and all in the space of a minute; but not ideal for extended observations and the benefits thereof, no.
This is simply not true.. Serious observation is very doable with alt-az mounts, driven or undriven. The virtue of an alt-az mount is that it makes larger apertures possible, makes them practical, and yes affordable.. Honestly, I have to think you have not spent much time with larger aperture scopes, "seriously studying" the many varied object within reach of today's amateur astronomer.
I doubt this discussion is of much use to Giovanni but I do believe it is important to clarify what is said on this forum. I get it that you don't like ALT-AZ mounts. Myself, I have both, generally prefer ALT-AZ mounts because of their simplicity, For smaller apertures, I use mounts with slow motion controls so tracking at high magnifications is not an issue. With larger apertures, the Dobsonian mount, properly setup, is very effective and much more practical..
(My two 12.5 inchers)