I've used mine with a WO Star71 which I think is possibly a bit heavier than the Evostar but shorter focal length (~350mm).
I've had good results with 30 second unguided exposures but It gets a bit tricky when guiding with longer exposure lengths.
It's definitely doable but I think it's getting near the limit.
Here's a write-up I did on mine a few years ago if you're interested:
hughsblog.wordpress.com/equipment/
The SA is great for widefield stuff too
