For those pondering how to fit the speedo sender to a slash 6 I offer the following as a possibility -
It's just a piece of 1mm stainless folded using a vise, wood blocks and a hammer, and drilled to suit. I used the magnetic bolt that came with the Acewell kit to replace one of the bolts in the hub - it is the perfect size (the one at 12 o'clock in the photo). The nice thing is that the sender comes off with the axle nut and is therefore out of harm's way when fooling with the wheel.
Routing the cable is another matter. For the moment it is zip tied onto the fork leg with a loose section running behind the gaiter. Probably best to run it up the brake line. Or maybe it can go through the gaiter somehow. I'll ponder that.
My headlight and instruments were trashed in a nasty incident with a cow, so I was looking for alternatives. I bought a chinese copy of a russian copy of a /5 headlight on ebay. It has a hole of 85mm diameter, and the Acewell is somewhat smaller (67?). I lathed up a donut of 6mm polycarbonate (90mm OD) with a rebate around the lower outside edge to suit the hole. This got a squirt of rattlecan black and it kinda looks like it's always been there.
I used a 3W normal bulb for the alternator light. The hole for this was already in the bucket. I like the Acewell a lot. I calibrated it using a GPS taped to the handlebar, adjusting the numbers until I got it right. I have fun holding the speed at 109.9 while going past police radar traps on the freeway.
My only issue with the instrument is that the LEDs are nowhere near bright enough during the day. I'm planning to bypass them and fit an arc of idiot lights over the top of the unit. As you can see, I'm not fussed at all about keeping things stock on my R90 slash 5.9.