Basically if the input RegEx matches, the signal is sent.
The component uses regular C# RegEx matching criteria. https://docs.microsoft.com/en-us/dotnet/api/system.text.regularexpressions.regex.match?f1url=https%3A%2F%2Fmsdn.microsoft.com%2Fquery%2Fdev15.query%3FappId%3DDev15IDEF1%26l%3DEN-US%26k%3Dk(System.Text.RegularExpressions.Regex.Match);k(SolutionItem...
Can also learn some basic RegEx here. https://regexr.com/
RegEx is NOT game specific.
Connecting to US servers from South East Asia? probably not great for any game outside of turn based ones, way too much distance for the ping to be anything but miserable for real time games IMO. But if you have local friends your playing with setting up a server locally is fairly easy, I recommend LGSM if you have a spare Linux computer (https://linuxgsm.com/lgsm/btserver/), works well when I host them (no clue about local server availability if your looking to buy one though).
You can also direct host, which uses steam P2P, so that just depends on how well your (and your friends) ping is to the local steam server.
I messed with that kind of concept myself for some time, though i only used it for switching between 2 guns on each side of a corner. Don't have a lot of experience in it, but perhaps some things i learned could be useful for you. I suggest using a range instead of an integer, since the game seems to have a tendency to skip the number you set in the expression if you are moving the mouse too fast. For example, the expression ^(1[3-7][0-9](\.[0-9]*)?)$ would trigger the component whenever your aim enters the range between 130 and 179.9999... degrees. That would also make you able to switch to the gun directly on the opposite side(though it's a big buggy without a delay). There is a pretty helpful website for making and testing regular expressions: https://regexr.com/. Also, connecting the periscope to a text display could help you set the range more precisely.
Honestly they're not that weird. Looks pretty close to these Here