Another thing to keep in mind about the spell sniper feat which I find really strange is the fact that, RAW, it allows spell attacks to ignore half cover and three-quarters cover. However, unless I'm mistaken, prone targets will still be attacked with disadvantage. To me, this is really weird because being prone is in essence a form of cover, but the feat doesn't explicitly say it, and the prone condition mentions nothing of cover. So a prone enemy can be 10 ft in front of Thaliss and will be attacked with disadvantage, and an enemy with 3/4 cover behind a wall won't, unless [MENTION=552]Creamsteak[/MENTION] rules otherwise.
Cheers,
SG