well it is down to the discretion of the immigration officer to decide. They can give the maximum on exempt on arrival, or they can give less if they so decide, depending on how they feel in the circumstances. Always worth a check to see what you get at the time and not just surmise you will get the maximum available for your passport.
A TM30 is a notification if the hotel/condo owner to immigration that you are staying at that address. So every time you change address the condo/hotel owner should notify immigration
A TM47 is a 90 day report which you have to do every 90 days, unless you leave the country and come back in. The 90 days is from when you enter back into Thailand, surmising you had a exit/re-entry stamp in your passport before you exited Thailand!