Would you mind to explain why you would split your funds that way?
OP was asking for the easiest and safest way for storing coins.

IMO the easiest and safest way is to just use a hardware wallet.
A hardware wallet basically combines the pro's of a paper wallet (private keys only known 'to' this one 'device'/paper) with the pros of a desktop wallet (easily accessable, automatically managing addresses, intuitive use).
While it gets rid of the cons of the paper wallet (no address management (change address), non-trivial way of sending funds) and the cons of a desktop wallet (security is based on the security of the host machine).

I really can't think of a way of storing coins which is as secured as a hardware wallet and is even 'easier' to use.
The only difference between a hardware and a desktop wallet in terms of usability is that you have to push a button to confirm the transaction. Can't get much easier than that.