UNS makes beautiful tanks. As a plug and play system, its up there amongst the best of them in terms of craftsmanship. I wouldn't rule out IM all together, their EXT line might be right up your alley and of good quality. Waterbox ones are nice if those dimensions fit your taste.
That being said, if I were to get a second chance at my build, I'd probably look toward UNS, Elos, Cade, and planet. I'd still go for a TSLOT stand, I wouldn't do another build without one now.
Autotesters have their place IMO. If you seek accuracy each and everytime, then you're right, there really is no dependable option. If you use it for trends and to give you an idea of how your system is running, I personally find it very useful. Letting me know when to change water, adjust my dosing, and preventing me from bottoming out on nutrients are just a few benefits.
AFA advice on going larger, I recommend putting all with in your budget on infrastructure. Bigger tank means bigger power...plan for that. An AIO can be ran on 1 circuit. I would highly discourage doing the same for a large system. Ensure you have adequate space to maintain things. Tight contortion in small spaces suck and will give you reason to slack off.
Know what you wanna keep and plan for it with intent. This will determine what flow you purchase, lights you run, and filtration. Know where you will run your wires and plan for wire management. No sense in creating a fire hazard that can burn your house down.
Some run with no skimmer, some undersize, others oversize....im in the oversized skimmer camp.
Buy once, cry once...some things shouldnt be skimmped on. Your return pump is the heart of your system. Buy a quality one, then buy it again to keep a spare on hand.
While a fully automated tank sounds nice, no matter how many devices you have running it, it will still take alot of labor in the first year or so till all stabilizes. I thought I'd be able to do just that. Sit back, enjoy the tank and have time for the little ones. As much as I put in, it still requires two half Saturdays a month to maintain. Not bad, just more than I originally anticipated. Automation is a different maintenance. You're swapping one type of maintenance for another...sensors need cleaning, probes need calibrating, etc.
QUARANTINE or buy 100% quarantined. Going through disease outbreaks is enough to make some quit. Save yourself the heartache and fish by ensuring you get clean quarantined residents. If you plan on doing it yourself, know that's its alot of work and a whole other side of the hobby you will have to learn. Go to humble fish for that if interested, otherwise, purchase your livestock from Kenny. It'll be worth it.
Defer to the expertise and experience on this forum and others. You'll never learn it all...and if you get close, by that time you won't remember..ask questions with an open mind. We got some great folks on here that chime in with very useful information. No one got time to learn it all themselves.
Most of all, have fun through the build process. You'll get sweated for staying dry for too long, don't sweat it..enjoy the process and include your kid in it as well...its something I wish I did with my first 4..
Best of luck to you and looking forward to watch your build.
