For the sanity score you can better use byte as value type since you can only go between 0 and 255. You can also use 2 bytes or 4 bytes but then you'll get a big number and i don't like working with big numbers. This is how you find the sanity score, (Sanity x 2)+57 so for example if you have 92 as sanity= (92 *2) +57 = 141.
You also have to know that 1 point of sanity equals 2 in your value found in CE, so if you have 92 sanity and it decreases to 89 it will become 241 - (3*2)= 235.
Also once your sanity score hits 1 and this will be 59 in CE i believe and you keep doing events which normally lower your sanity. Your sanity will stay at 1 but the value will keep decreasing once the value reaches 1 and you go lower it will start from 255 again. Now keep in mind that after that you will not be able to adjust your sanity score anymore, it will stay at 1 no matter what.