How much should I feed my turtle ?

Bruinybear

For a RES in the size of 13cm, a full tea spoon will be fine, for 9cm yellow spotted, 3/4 tea spoon is better.
For your other question, please understand that most turtle do not like to be handled, of course there will be exceptional (rare possibility) but in general it causes them stress when being held by people.
I have also seen some youtube videos which shows interactions between owner and turtles, some owners have several turtles and each of them has different "personality", even when some of the turtles are raised by the owner since hatchlings, some remained extremely aggressive whenever facing any interaction, while some tend to adore handling.
Although you may attempt to tame/make them more adapt to your existence by letting them out of their tank and walk around the house with you watching and guiding, there will still be great possibility that they refuse to be handled even after a long time.
Turtles don't have the same affection like other mammals, instead of "unconditional love",they are more towards choosing objects that makes them feel comfortable or warm. My turtle like to stay on my palm mostly for the same reason, its like conditioning, its brain link me(my palm) and positive feeling together, hence it looks like it has affection towards me(approaching me/my palm). Likewise, over handling them when they have already shown negative reactions could cause them to have bad impressions towards you(except for feeding time becuz theres an external condition.)
Hope this helps! :)