Acid-test on Throws

Question: with a throw of 23 and thumble/balance results of 25&21  , do i receive/avoid any form of damage from sprunging green tree like a thrown object?    should the result of the throw be 19 (-4) because it was improvised or we should not consider a familliar as improvised when hurled?  Any easy way to calculate our distance throws and max weight?    how much a Medium size with X str limits compared to Large size with X str? Example: Does Limar's superior strengh throws a equal or lesser object volume  compared to Sidsaspi? Is the thrown thing count as improvised all the time?  a rock, a person , a branch..etc? Is the throw still  dex related  and static for str.? (the internet is giving me 3 different variant from 3 different books: unclear PHB, Race of stone and Complete Warrior)

Anything (or anyone) that isn't manufactured to be a weapon is considered an improvised weapon, unless you have a feat giving you weapon proficiency with it (representing practicing enough to get used to wielding it). Per the PHB, range increment for an improvised thrown weapon is 10 feet, and max range for all thrown weapons is 50 feet. The max weight of an improvised thrown weapon isn't specified, but I'd probably base it on equivalent manufactured weapons for that size character (so for a Large creature like Sidsaspi, it would probably max out at around 20-24 lb). Str mod applies to the damage rolls, not the weight throwable. Dex mod applies to the attack rolls, as with a normal ranged attack (as well as any bonuses that would apply to normal ranged attacks, such as BaB).