I have been using a 4x5 Master Technika for 10+ years, but there are times when I really wished I had a monorail. Given that I have many Linhof accessories and lenses, it would make sense to consider a Linhof monorail for architecture and urban landscapes. I am working on a night project needing long exposures (up to 10 min), and a stable and rigid camera is a must. Though the TK 45s is more portable, the Kardan GT is probably more rigid, albeit heavier and bulkier. It sounds like the TK might be the better choice given its greater portability while still being sufficiently rigid. The Kardan is probably a little more robust and rigid, but at the expense of weight, size and portablity. I have two Linhof tripods, both excellent, but for different purposes - the Twin Shank Pro (3317) and the much heavier Profi 3 (3454). I use the Profi 3 for night photography with my MT and a Profi 3 Universal Pan/Tilt Head (3669) - a heavy combination but absolutely rock-solid for long exposures. Moving forward, I see two possible combinations of cameras, heads, and tripods: (1) Technikardan 45s, 3-Way Leveling Head (3663), Twin Shank Pro Tripod (3317). (2) Kardan GT, Levelling Pan/Tilt Head 90 (3668), Profi 3 Tripod (3454). The Profi 3 has a 90mm clamp mount for the Levelling Pan/Tilt Head 90, and the head accepts the Kardan rail directly, permiting sliding back and forth and locking. This would be the ultimate combination for stability and rigidity, but it would be heavier, bulkier, and less portable. If I was considering only daylight photography, the TK would be the better choice, but as you can see I am still torn about the right monorail for night photography. Am I just obsessing between 98% vs. 99% of perfection, or is there a bigger difference than that between the two above choices? Many thanks for your advice!