I did the modification today, works like a charme!
The 245 in 1 cartridge shell isn't the same as original standard carts. You have to squeeze the back half, not the front half. The plastic is so flimsy, you don't need quick grips at all. Just squeeze the cart's back side with one hand and pull the front half with your other hand.
There are 5 clips in total. 2 at the left side, 2 at the right side and one clip at the top