Yeah there aren't a huge amount of chunks in this game but remember you only need six for full upgrade and also - bonfire ascetics exist. Use ascetics at poison pool and grab the 3 chunks there for an easy farm. Way quicker and painless then farming Gyrm or the Coal Tar Snakes. 2 ascetics for another upgraded weapon is pretty good, especially compared to Twinkling/Petrified. You can also get pretty much infinite ascetics once you reach Drangleic Castle and do the Pilgrims of Dark areas, since the enemies there consistently drop ascetics. So honestly not bad, and pretty great compared to games like Bloodborne

Unbearable amount to get. Have 12 slabs, 0 chunks, and maxed 3 weapons, no armor. Beat the base game and 1st dlc. Guess i'll dump more of my soul memory into buying them, because the farming is unbearable too. love dark souls 2.

coal tar?

Ascetics make grinding bearable.

I have 8 titanite Slabs and 2 Chunks lol.

It felt like I got more Slabs than I did titanite Chunks, while I did split my materials quite heavily across armor and weapons, it was only after beatimgmthe game (havent completed any DLC yet) and getting access to a unlimited supply of them that I was able to upgrade my armor past +6. Which is why I did that to begin with.

For whatever reason it felt like titanite Slabs were more common than titanite Chunks. Which doesn't make sense to me.

You are able to get a +10 weapon before even killing a boss in this game (pick petrified something gift and hope for a slab), get a +3 like normal without issue, get cat ring and go to the gutter and hard farm Coal Tar's for the 6 large shards for +6, get the 1 chunk from shaded woods by getting fragrent branch from gutter to gain access to there and farm the remaining 5 painfully from Coal Tar's, congrats, you have now gotten a +10 weapon with literally 0 boss deaths in your game. now have fun as you'll also have RTSR from shaded woods too and are probably around level 50+ from farming, let the killing spree commence.

Bell Keeper's covenant can also allow for good titanite chunk, slab , twinkling titanite or petrified dragon bone farming.

I've had one drop from the Flexile Sentry in Sinner's Rise in SofFS. Not sure what the drop rate is, though.