Hi,
Your Skyguider Pro is a good start for wide field DSO astro. So if your goal is mostly DSO, that's a good way to start and stay for a while. It will be limited in image scale, using shorter lenses and a larger sensor like you currently have. I would not press towards a telescope for this purpose, its not needed. The point of a telescope would be to increase your image scale (such as high resolution lunar surface imaging like you mentioned perhaps). The Skyguider Pro however is limited in terms of using a longer optic, be it a lens or telescope and the reason for that is mass and moment arm. The telescope will have more mass than that mount, plus a camera and other gear, and it will have a long moment arm from just its length which will result in torque and oscillation which will ruin long exposure. So just to reinforce, you have a perfectly fine setup to start out with long exposure wide field DSO (nebula, galaxy, clusters, etc) with any camera capable of long exposure (bulb on your dSLR) and any simple camera lens will do this work (I would not explore a telescope for this purpose on this mount). I would use something smaller and simpler than your Tamron zoom though, something more like an 85mm or up to 200mm that has faster focal-ratio so that you can stop it down for a flatter field and less coma (such as an 85mm F1.8 operating at F4; or 200mm F2.8 operating at F4; or an inexpensive M42 mount Super Takumar 50mm F1.4 or 200mm F4 classic legacy manual lenses with adapters, they're cheap, sharp, and good).
If you want to explore telescopes and get more into high resolution lunar surface imaging, that will require a much more robust imaging capable mount. And your entire budget would need to go towards that to begin. This is also important for any imaging in the future as you will expand into other things. The mount is everything with imaging, no matter your subject. So if your goal is to move into telescopes and solar system imaging as well as DSO, you will want to put the most of your efforts and budget into a mount now instead of later because it effects everything. Everyone tends to want to do the opposite, get the lightest inexpensive mount and think they'll get a telescope, camera, etc, when that's the opposite of what they need to do, which is get a heavy duty high capacity mount and stick with smaller optical instruments.
So my suggestion is to just use your max budget and put every bit of it into a mount. Something in the 30lb class range, like a Celestron AVX, Skywatcher HEQ5 or Orion Sirius or iOptron CEM26, etc. And then use your camera and lenses on this starting out. These are entry mounts, but they are magnitudes better than a tracker is and will be able to competently image with telescopes, so that you can grow into the imaging and not be limited out of the gate by a tracker that cannot handle weight. You can image with your 7D2/R (video mode and long exposure single still shot).
In the future, after a good mount, then consider moving towards a telescope for your lunar goals (something with a larger aperture like a 6 inch (150mm) or 8 inch (200mm) newtonian or SCT telescopes) and then just keeping imaging and learning from there. But it all starts with having a good mount. For DSO, stick to a short but good camera lens, or eventually consider a very short APO refractor, like a 60~80mm F6~F7 (but a camera lens works just fine too starting out!). Don't worry about large aperture for DSO right now, just look at focal length for image scale. But you're set for DSO for now, for your goal of lunar, again, look at larger aperture instruments like mentioned above (big aperture, more resolution potential, secondary to seeing conditions).
Things I recommend you start looking into:
Astronomical Seeing (this is crucial for imaging high resolution, like lunar, planets, solar, etc; and fine image scale DSO)
Image Scale (pixel size relative to focal length)
Aperture (the physical size of the opening into your optic, not to be confused with focal-ratio; don't worry about having "fast" optics)
Dew Handling (keeping your optics from dewing over, humidity, warmers, etc)
And of course familiarize yourself with objects in the sky
Check out CloudyNights for heaps of info:
https://www.cloudynights.com …ginning-deep-sky-imaging/
https://www.cloudynights.com …ar-observing-and-imaging/
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Summary: Put your budget into the best mount you can first. Imaging starts and ends with the mount and it determines what you can and cannot do very frankly. So as you expand into astro in general, the mount is what matters the most.
Consider if you need this to be mobile or if it's just in your yard, etc.
Very best,
