I will just comment on the Compeed method. I have been successfully using this for 6 months. I use a 4mm leather punch to make a hole in the plaster but generally very similar technique to that described in
this thread. I also make use of a mirror to help in aligning the applicator to the circle.
I still get a reaction under the 4mm hole, it is very visible when I remove the sensor, barely visibly after 2 weeks and gone after 4. However this is the only apparent side effect, I have not noticed any itching or discomfort.
The compeed does not adhere very well, and I find that the edge of the plaster (and thus sensor) often starts to lift before the 2 weeks is up. When this happens I cover the whole thing in a square of Opsite. Starting with my current sensor I now put the Opsite on immediately when I apply the sensor.
Until 6 weeks ago I have not noticed any decrease in accuracy. But the last 3 sensors have all given accuracy problems always on the low side (1-3mmol), I think the start of problems on these sensors has coincided with the compeed lifting. The current sensor is 1 week in and just fine.
Good luck.
Tim