How to get Mel to print Radiant quicker?

Hello,

I'm loving all the Mel flex comps, been trying to flex her into a few other comps I'm cooking up.

My question is, I can't seem to get her to print the radiant item at all.

For example, in my most recent game, I got her on 4-3 with 2x Nashor, 1 JG.
By the time I won the game around 6-3 or 6-4, she's still like 20 mana short from the first Radiant print. Is there a way to fasten this? or would that result in lower performance.

Thank you,