I managed to get out with the SmoothShooting Westy Tray at the weekend and can certainly say that it makes loading Daystates a lot easier when in single-shot mode. You hardly have to look as the steep-sloping sides roll the pellet into its track in front of the probe, and there's not the risk of pellets rolling out the other side as with the standard tray.
Have a look at the profiles of the Westy (top) and standard tray (bottom) to see how it works.
You'll also notice that the Westy Tray has four fixing magnets whereas the Daystate has just two. However, the Westy lacks the locking pins that keep the Daystate tray rock solid and, although it has locating skirts on either side of the contact point, there is some discernable creep from left to right - probably just a fraction of a millimetre, though. The absence of those pins means you can fit the Westy either way round so it can quickly and easily be switched from left-hand to right-hand loading.
In use, the all-important alignment seemed to be perfect and there was no hint of contact with the loading probe or its O-ring.
Loading was much, much easier although it is harder to retrieve pellets from the deep-sided Westy should you happen to chuck one in the wrong way round!
On the range...
These groups were shot from at bipod at 40 metres with a steady right to left wind. The red target cicles are 10mm across. Groups shot with the Daystate tray are on the left and the Westy on the right.
As you can see, there really is very little difference in terms of down-range performance, and the shot that strayed slightly high in the top-right group can probably be put down to the weather conditions.
How it looks...
The Westy Tray is very well engineered and really doesn't look like a retro-fit gadget. Here it is on my Daystate Mk4.
For more info, see http://www.smoothshooting.com/