Lucky dog!!
I think you already have the answer,you say the XRB and PRL can double easily.
So, I think you should hold them without doubt.And the other,you can sell a half to get
more cash!If the whole market goes down,you can get more coins,on the other side,if
the market keep bull,you also can earn pretty much profit with XRB and PRL.
Above is my opinion!Finally,you have to make a decision by yourself.