Hi, I am using a PCS2000, and my toddler has yanked the head so that its drooping a little. Placing a bubble level on it, the bubble slips from middle, but still sits roughly in the centre of the chamber, whereas its perfectly centred on the base board. Things straighten up a bit when I lock the head off. I am wondering, whats the tolerance for alignment? Its obviously got some "tolerance", of the order of degrees, so that its the same whatever the enlargement, logically. I guess, having seen in a Zeiss MTF document some flatness of field discussions that this tolerance is actually very small, but its a cosine relationship, so initially the fall off in performance is slight and then accelerates. I dont want to replace the PCS2000, as its one of two, and I am getting to understand the filtration adjuster now. Has anyone shimmed the base column on one of these...what material would you use, or, given its aluminium....could you file it down/machine it! At least the photo is sharp in the centre. Separately, I am looking at split grade printing, and last night was mucking around with 4s intervals. This left me with 16 different exposures on one 5x7 print. But the 4s steps seem too granular, so exposure steps are too high, although I do get a rough idea of which mix of blue and green I want. I was printing with Kodak -ve filtration of 10 blue or 10 green (half power basically). It strikes me when I wind the filtration right up to turn either the blue or green light "off" there is still light coming through the blue and green channels, which means I am not getting pure blue or pure green. If I use higher filtration, it wont really be either blue or green light coming through (I am aiming at mixing 0 and 5 grades). I dont think I could do with less than 5s intervals. Maybe I start using f11/f16 on the lens for fine tuning the mix of blue and green, and then just reduce the final exposure by a factor of 4, when stepping back to f5.6/f8. Anyone have practical experience to share with the PCS2000 and split grade printing please?