If your not in a rush, keep an eye on redbook average sales prices, I've notice the 2007 v8 calais have gone up a bit recently. No idea about other models as I haven't been watching
Test dive them as you said is way to go. This is how you will really know. It's not until you have a drive will you know if a car will live up to your expectations. Lockdown seems to of reduced supply.
I'd also look at auctions to see what there is. There will be allot more VE/VF SS to choose from compared to HSV. I like the look the look of VE SS Wagon.
They are sort of car you could buy and never want to sell. You would just keep it and buy another for a daily in the future.
You might prefer the look of a VE, but its massively different to the VF
Also plus 1 to test driving some. I'd never driven a commodore before buying mine so made sure to try out plenty and see what I liked (SS, Redlines, HSV, manual, auto)