Noob with New Rpi4 Install ?s Hangin Me Up - 2020…
First thank you all for all of your hard work and community help! You Rock! Thank you! 
Second I apologize for this being a little long winded. I felt most of the details might be important. Sorry! 
- That being said you can just skip to the “QUESTIONS” below. lol
After many hours/days of research I decided on HA (Home Assistant) over openHAB and HomeSeer (hello everyone at HA!).
For simplicity and learning I also decided to “start” with Rpi4 (as opposed to the many computers and NASs I have running 24/7).
I’ve read (to much imo - lol) the whole HA, HassOS and Hassio/Hass.io and different naming/installation choices, etc. (so please don’t turn my post into another debate, lol) So coming from a noob to answer your question… YES it is extremely confusing. lol
That being said I am leaning towards “starting” with new “HassOS 3” on the Rpi4. It sounds perfect, with the only major CON (and therefore my only initial concern o far) is being able to utilize the USB SSD more then the SD (more on that below).
HARDWARE:
So I have narrowed it down to starting with the following hardware (will be here tomorrow, Saturday):
- Rpi 4 4gb Canakit
- 2x Samsung Pro Endurance 64gb Micro SD Cards
- Kingston A400 240gb SSD card with StarTech USB to SSD
- Aeotec Z-stick Gen5 USB and right angle adapter (which in theory should allow it to work as opposed to a “hub”)
- Rii i4 Mini BT & Wireless (USB dongle) Keyboard/touchpad
- Some Z-Wave Multi Sensors and Plugs to get me started
- I should note the main goal is to use HA with my HAI OmniPro II as well as my Russound CA6 Audio/Video (for now) - JIC some users have experience with these, PLEASE PM me for future!
- Lights TBD (possibly Lutron Caseta or RadioRA2 atm for reliability and being able to use them all manually if HA is down, etc)
QUESTIONS:
1 - Where/How do I install the latest “HassOS 3” for RPi4?
Also which is the latest/best “Installation” instructions/guide to install it on the Rpi4?
As I have seen a few but the are not using the brand new “HassOS 3”. And the official Getting Started seems to be device “images” or “VMs”, etc.
2 - During and/or after install can I do “something” (using “HassOS 3” if possible) to utilize more of the SSD and less of the SD, to eliminate the slowness and killing the SD cards?
I realize boot from USB on the Rpi4 (especially with “HassOS 3”) is not officially supported, yet, etc. (I realize it is around the corner). Though I have read about other successful techniques like booting from the SD but running from the SSD. And/or using a different DB and/or putting it on the SSD, etc. Ideally I can do “something” and still use most of the benefits of the “HassOS 3” (add-ons, update and back-up ease, etc) even if some tweaking is needed before/after each update/install, etc. which seems to be the biggest benefit of the “HassOS 3” (which also locks it down a little).
3 - If #2 is not possible with “HassOS 3”. What is the next “best” and most similar way (for a Rpi / HA noob with some web programming experience since the early 1990’s) to pick an OS and install HA with being able to use Add-ons. I love the idea of being able to implement an easy backup, update, test, and then rollback (if needed) process, especially being a noob and the frequent updates, etc.
4 - Wether using #2 or #3 above. What is the best way to have a complete, easily updated, ready to go entire SD/SSD setup backed up (to another drive or computer/device) that can be implemented incase of SD and/or SSD failure?
Doesn’t necessarily have to be a “mirrored” bootable backup of both the SD and SSD card, if that isn’t as easy or possible (but would be nice - lol).
I think that is enough to get me started and more then enough for this post (sorry guys/gals).
But I felt everything above was important and related during the initial install and setup, etc.
PS - Anyone have experience with HA with OmniPro and/or Russound please, please PM me. 
Thank you all so much in advance! You Rock! Drinks on me! 
Geo