Q) The kit comes with yellow poly bump stops. Should I use these, the OEM bumpstops with the integrated boots, or both?
A) Lowering a Mk 1 can cause problems with the rear suspension bottoming out. Since I was not going to lower mine too much (13.5" from wheel centre to arch lip on the rear) and the rear Gaz shock bodies are shorter than the originals (so more travel) I decided to stick with the original OEM bumpstops. If going very low where bottoming out is more likely to occur the yellow stops included in the kit may be better since they appear to be more progressive, i.e. they seem to start off softer. A good compromise may be to hollow out the OEM stops and fit the yellow stops to give a softer landing if/ when the suspension bottoms out, but there are undoubtedly people better qualified to confirm this.
Q) The kit comes with some washers, where do they go?
A) These fit between the bumpstop and the top mount and their purpose seems to be to raise the top mount sufficiently to ensure the top nut does not run out of thread. Not sure why the thread on the shock piston is not cut lower, perhaps it is a common part and to produce a longer thread would involve added expense, or perhaps it is to cater for aftermarket top mounts. On the rears, with the OEM bumpstops and top mounts I found one washer was sufficient to ensure adequate thread depth into the top mount. However, if the yellow bumpstop is used in place of the OEM stop two washers will be required, due to the loss of thickness of the washer built into the OEM stop. On the fronts I used two washers on each shock to ensure the plastic covers would seat on the top mounts, otherwise the piston rod would have projected too high. The loss of travel due to fitting two washers as well as the bumpstop should not cause bottoming out problems on the front as there is a lot more suspension travel than the rears.
Q How do I locate the concertina gaiter, there’s no lip like the standard shock?
A I found my plumbers merchants stocked a washer (50p each) which did the job perfectly - see photo.
The internal diameter is approximately 2". Hacksaw through and file off any sharp corners and the washer will screw up and down the shock to the desired position and still locate firmly enough not to move by itself. The gaiter will engage over the lip of the washer. Due to the small seating diameter of the spring the spring has to be fitted before the washer which makes adjustment a bit fiddly, so it is best to wait until you have set the height up before positioning the washer and slipping the gaiter over the lip, so you only have to do it once. Waxoyl on the shock threads will make screwing the washer up and down a lot easier, alternatively it can be levered up or down with a blunt screw driver inserted between the spring coils.
Q) What height should I set the spring mounts to initially?
A) After much trial and error I found a dimension of 232mm from the lower shock bolt centre to base of spring gave a height of 13" wheel arch lip to wheel centre on the front. A dimension of 148mm on the rear gave a height of 13.5" - see photo. 
Each turn of the locknut will raise or lower the car by about 2.5mm, so adjust the above dimensions accordingly to suit your desired height. These are only estimates as each car will differ slightly but this should give you a good starting point and save you some messing around. The threaded grub screw hole on the spring seat collar can be used as a means of keeping track of the number of turns up or down when raising / lowering.
Q) What setting should I use for the dampers?
A) This will depend on personal preference and I’m still experimenting but I’ve found 16 clicks on the front / 28 on the back to give a good balance of ride and firmness. 