How to power up 50 LEDs? (DIY 'fireflies' project)
In each branch you will need a current control resistor so use 7 leds instead of 8 which gives you a 21.7V  drop. Your resistor needs to be (24-21.7)/0.1 =33ohms. You can have up to 1.25/0.1 =12 branches on each supply.