Malcolm.....if you look in my BS400 review, at the setting the fence square section...you'll see the Oneway in action for more than just planar blade setting. It's a very versatile dial jig and magnetic square for anything with cast iron. Very useful and very accurate.
I had the PT260 before I got the Startrite and the blade setting is fiddly without question but it is relatively easy to master. And once mastered it's easy. I received that little jig that comes with the machine that everyone badges too and it is useful for one thing and that's holding the spring loaded blade at the right height. It's magnets clamp on the block while the adjustable feet determine blade height. The big problem with them is you have no idea what blade height actually is because there's no easy point of reference since as another poster mentioned, they don't reference the outfeed and blade accuracy is critical relative to outfeed to avoid snipe. However, when you have a dial gauge that's sufficiently heavy duty as the Oneway Multigauge, it doesn't matter that the beds are aluminium because its heavy duty enough to stay put anyway ie without any magnetic assistance.
With the combination of the multijig providing the exact 100th milimetric calibration of height above outfeed and the micro adjustability of that cheap tat Taiwanese jig, it works an absolute treat and you can dial in literally any height you want. More importantly you KNOW what the height is, empirically.
I spent a good deal of time experimenting with this because the lack of accuracy over plane blade setting was really bothering me some years ago. In the end, this combination was the perfect solution and in fact before I hit upon it, I used the moving wood block technique for years. And it was never that accurate. In particular, you would get small variance across the block so the planing would be marginally uneven, this really shows up when thicknessing. Essentially the job would be slightly tapered across its width.
The beauty about that crappy cheap far east jig that every one and his wife badges is that with the 260 in particular the knives are spring loaded as I recall. The challenge was getting them pushed "down" to the correct depth rather than pulling up as with most other machines. That little magnetic foot on the jig is really good at holding the knife down and then using the oneway to monitor the actual height above outfeed. There is a screw adjustment on the other jig that pushes the blade up or down while you watch the oneway dial gauge.
All other methods I investigated are anecdotal in nature ie they don't measure actual height empirically above outfeed which means you have to go through a laborious process of...use method....check results....use method again to adjust.....check results....adjust again cos the middle knife is now too high...aaaaggggghhhhhh. I found it very frustrating and fiddly. With my approach, you can read straight off the dial actual height and in theory no further adjustment needed. I wont go into what happens when you've adjusted all three knife height points with pin accuracy...then tighten the grub screws only to find its wound the accuracy out again...but that's another story!
I found the 260 to be a truly remarkable machine given its weight, capacity, block size, 2 knives only etc. It was absolutely brilliant, a real little work horse and my only frustration (after I cracked the blade setting) was the speed of changeover from planing to thicknessing. Beyond that, I always thought that machine punched way above it's weight and if I end up with a smaller workshop one day which is inevitable I guess, I'll buy another without hesitation.
I sold mine in the end to a mate who moved to a centuries old French farmhouse and he has planed all the solid oak beams from rough using that, 100's of metres of rough sawn French oak. And its still going strong 7 years later