Yussel, You don’t just say a hesped randomly. What would happen in the yeshivos i learned in is that at the end of shiva, they would finish seder at 6 (instead of 7.30) and the Rosh Yeshiva and a famous talmid of the niftar would speak for say 45 minutes each.
You cant expect that to be arranged on the day of the petira at a few hours notice.