If I use the OBSE version of the CS, does this mean the mod I make will only be compatible with OBSE games or does it only cause this if I use an OBSE function.

Currently if I want to make a non-OBSE mod I am using the default CS just in case the OBSE version makes it require OBSE.

Anyone know if it's safe to use OBSE version all the time even if I want to make a non-OBSE mod?

You can use the "OBSE-version" everytime. Your mods require only OBSE if you use OBSE-functions in them.

Actually I'm not sure that's true anymore. Iirc, the last two versions of OBSE (18 and 19) now require your users to be running OBSE even if you don't use any OBSE functions. I think it has something to do with the new string (or array?) handling. I know I had to go back and specifically recompile all my scripts when one of my mods didn't require OBSE. I'm pretty sure I saw something in the previous OBSE thread about this. You could ask in the OBSE thread to confirm (in the mods forum).

Edit: I see Filly asked in the OBSE thread and it turns out it's safe. I must have misunderstood