I'm trying to get Mavda's rewards for each tower, and I know that I need 800 from Sheerdrop Spire. I found that for Treetop Tower, night was best for flesh hunting (tons of ogres, plenty with purple that dropped dripping/pulsating flesh).
Is there a "best" time of day to go through Sheerdrop to gather enough flesh? Or a particular path? I'm in there at night currently, and all I'm finding are bats...
I waited until I was at the end of the game so I could max Aeron to level 40, maxed out all my weapons, so when it came time to revisit the towers, killing the monsters was very easy and fast. I equipped Aeron with the Twin Blades to allow him to move faster around the towers and I scouted rooms for flesh hunting. It's really not hard at all once you're powered up, I was able to amass 1500 vetos of meat in the Dawn/Dusk tower before Elena even began to transform... I could probably amass 3000 vetos of meat in one go, maybe, but it's not as hard as it seems IF you wait to do it until you're more powered up.
I just managed to get the 800 from Sheerdrop the other night, and I managed to end up with a spare Pulsating Flesh to feed Elena. Oddly, daytime was the best time to hunt.
Head into the tower in the morning and go through the door behind the statue. If anything's here (if you're lucky you'll get an ogre), kill it, then use the elevator. Don't take the ladder shortcut.
On the second floor, go through the door and take a right. There's an ogre that spawns here, so kill it and get its flesh. Head to the left, grapple across the broken floor, and go through the door.
Three wolves! Kill them as fast as you can (I like grappling one and swinging it to knock the other two over). Make sure to grapple their bodies for the best flesh. Keep going to the exterior of the tower.
During the day, there are birds instead of bats. They have a chance of giving you beast flesh. Typically there are two outside. Don't take any of your ladder shortcuts at the moment; use the elevators until you're on the fourth floor and head inside. There are two more birds that spawn here. Leave the same way you came in once you've dealt with them.
Back on the exterior, use the elevator to go up to the fifth floor, cross to the other elevator, and start heading down. I prefer dropping as opposed to using the ladders; it's faster. Have a drink from the fountain if you need it, then go inside and head for the chain room (sometimes there're another two birds). Poke your head in the chain room and leave immediately.
Backtrack to the fountain and keep descending via the ladders, killing any birds that might have spawned. At the bottom, the three wolves will probably have returned, so take them out again and keep backtracking, because both ogres will probably be back as well.
Lather, rinse, repeat. Always yank from the body for better flesh; be careful not to accidentally fling the birds off the tower.
In three or four loops, I collected 950 leots worth of flesh - after giving Elena a pulsating flesh, I still had 850 left over to sell. Make sure your bag is as empty as you can get it; I had 25 units of beast flesh at the end of the run. It's pretty quick, too - Elena's gauge was at 7/8ths full (from dripping flesh) when I started, and I made it back before she'd transformed at all.