I'm actually thinking that I will stay with the bigger ones because they will last longer, although your point about just using them up faster without worrying about bigger mushy bits makes sense. I have one of the round ones in the shower now (I think they are about 4 oz). After about ten showers (I think, not sure because my niece may be using it too) - using them pretty lavishly on my arms and legs - it got thin enough to break and I just smushed the pieces together to finish using it. I have NOT been good about keeping it out of the shower/away from heat and steam, though. I think it would last much longer (and it would be a good health/safety measure) if I did, so I'm glad we had this little talk
How many showers have your Buffy dupes lasted for? They are an expensive indulgence because they are 2/3 pure butters and the whole point is that they melt, but if you make them yourself I think they are so worth it! I am too cheap to pay $14 for 3.3 oz at Lush, though.
ETA: I was a little worried about them getting moldy or otherwise nasty in the shower, but decided with them being anhydrous and then adding the preservative they should be OK. Plus Lush has had them on the market for at least a decade, that's somewhat reassuring!