4GB or 8GB of RAM for XG Home?

Depending on what features you will use, or on how many sessions the firewall will have to handle, 8GB will be much better than just 4GB.

So, get 8GB.

Doesn't home edition only use 6GB max no matter how much RAM is on the system?

Right now I don't know.

Since v18 EAP the limit has been removed from my installation, even after re-imaging It, It still doesn't have the 4C/6GB limit.

Even then, the limits are done over grub at boot, if you remove them on your installation, the artificial limit gets removed.

Oh! I didn’t know that, thanks.

Seems not to be enforced on VM installations from my reading of posts.

My hardware has 8gb, but after a reboot during upgrade displays 6gb approx.

an

Same for me. I’m running v18 MR-4 on bare metal and still able to utilize the full 8GB on my Qotom device. As you mentioned, it’s been like that since v18 EAP. That being said, my memory usage usually sits around 40-45%. I have pretty much everything enabled (IPS, ATP, etc.) to include HTTPS decrypt & scanning with about 25 devices total on the network. 

Same for me. I’m running v18 MR-4 on bare metal and still able to utilize the full 8GB on my Qotom device. As you mentioned, it’s been like that since v18 EAP. That being said, my memory usage usually sits around 40-45%. I have pretty much everything enabled (IPS, ATP, etc.) to include HTTPS decrypt & scanning with about 25 devices total on the network.