Erhua and reduplication If I want to say "a little" of something I might say  一点儿 yìdiǎnr.  Or I might say  一点点 yìdiǎndiǎn.  But I do not feel right using erhua with reduplication.

It sounds wrong to me (and maybe I am just wrong about this) to say either  一点点儿 yìdiǎndiǎnr  or 一点儿点儿 yìdiǎnrdiǎnr.  Is one of those reasonably normal?  Are both? Or what?

For simplicity suppose I am talking with university people in Beijing.
In spoken language, northerners do say 一点点儿 or 一点儿点儿 sometimes, but not all the time, it depends on the situation. It is not wrong to say those words with erhua.

However, I don't encourage Chinese language learners to learn them because 


it is not really that important 
it doesn't really change the meaning 
it is hard for learners to say them in a natural way 
you don't have to sound like a northerner.


I believe correctness is more important and sounding natural.