Is it better to read the Tikkun all night or learn Gemara or split the time in half?
Rav Yitzchak Abadi z"l learned all night. He did not say tikkun.
Did he tell others to do the same?
The Rabbi advised learning over Tikkun, Tehillim etc.
However, it’s not a hard rule and Hakol Lefi Ha’inyan. One of the Rabbi’s Talmidim who is a Rav spends the night with his Kehilla saying the Tikkun with the Rabbi’s guidance. Because that’s what works for that community. You wouldn’t find them in the Beit Midrash learning Gemara all night. Just not who they are…