Having problems getting a smooth printing experience  

Having problems getting a smooth printing experience

I have an original MK3 that I _finally_ got upgraded to MMU2 - and because this has been WIP since mid pandemic, I have a few spools of filament that's been sitting in my basement where the printer is, some in the open, some in a sealed bag. I've used a filament dryer but I still see issues with "old" filament. Generally it doesn't stick well to the textured surface. A new spool that has been in a vacuum seal doesn't seem to have as many issues - but several different filaments (PLA/PETG) have a hard time staying stuck to the plate.  Doing the first-layer calibration print, it shows up by having the left/right side of the little squire printed lifting up. Same settings, PETG, prints well, so I suspect the filament. HOWEVER ....

I'm really regretting doing this. Yes, I have several types of prints that should be possible now (multi color) but what a bad setup. From an impossible "buffer" (ie. hard to load anything) to an extreme trippling of the size needed to print. I have a shelf about 1m above the printer that I used to have the filament feeding into the printer on but I am seeing all kinds of problems using the units that come with MMU2 to provide a smooth filament feed to the printer. On change I see old (burned!) filament coming out which definitely does not stick anywhere, just getting filament loaded into the MMU2 is a struggle - particular if the spool is on the shelf, then the MMU2 is struggling pulling the filament through - so I am suspecting that the fill-rate isn't as high as it should be.  In other words, what I used to do in a few minutes  (changing filament) is taking forever to load.  I understand that once loaded I don't need to continue to switch it out, but if it cannot be pulled through it's all for not.

For now I've wasted a lot of filament as it breaks trying to "loop it through" the buffer, or pushing it "hard" into the MMU2 that isn't catching it (I can see it spinning). Eventually it works but it takes FOREVER to get working and with a lot of waste.

On top of that, there's no way my enclosure will fit - even if I cut small holes to feed the filament through. I'm going to think about perhaps adding ptfe tube mounts to allow the filament to be fed from the outside in, perhaps I need that buffer put on a shelf lower than the 1m above the printer I have now and more stuff to guide/slide the filament into the buffer.

Please share a picture of your setup. Where do you have the spools? Can you make the black plastic ones work (my rolls fall off very easily when the filament is pulled by the printer, particular when I use the shelf), do you have a great way to mount/use the buffer that makes using it easier than sitting on the back of the printer?  I'm a bit desperate - pretty much thinking I need to downgrade to MK3S+ if I cannot find a way to make this work.

I can definitely handle having to dry the filament if that's the issue - that's what I'm doing now. But it feels like the feed rate may be part of the problem too, hence my post.