So I am in the first few weeks of using my big box dual. Flawlessly printed about ten objects. If I had my time all over again I possibly would have bought the single rather than dual head, but most of the time if I buy a design that doesn't work well I have fun upgrading it. The problem is that the big box dual design isn't a really good platform as it stands. Trying to fix the two heads to be identical height and in line is virtually impossible. If the two heads are even a single layer thickness different in height then the lower one will remove the layer deposited by the higher one. Moreover the only adjustment you have are at 180 degrees from each other so you can go up and down but have no adjustment for side to side. Inevitably there is side to side movement. So you end up after a lot of work with two wonky eye'd nozzles but at identical height. Now if this was actually the case I could live with it, but it isn't. The bodies fit into a printed hole and are pushed against an oring. Compression of the oring gives a degree of adjustment defined by the two grubs screws either side. Problem is that after the shunting of a print there is significant movement in this arrangement. It isn't a system stable against the vibration of the print. So much so that my dial gauge has read nearly 150 microns height change after a two hour print. So in order to print dual head I am having to adjust nozzle heights on every print, which then means I am having to feed in offsets in Y on every print as well. I can see why most people seem to leave comments that they are only using one head of their dual head printer. So the reason for this wordy post is to ask if anyone has removed the rubber oring an replace with something much tougher or got rid of the oring completely. Lastly and god forbid but has anyone actually glued/fixed/shimmed their bodies rather than use the adjustments.