Ikkle test results for boiling 500ml of cool tap water using: 15ml of Ekofuel bioethanol, Toaks 700ml pot and Trail Designs cone w/ 10mm insulated pad under the Ikkle. Setup gave a flame gap of 25mm.
I've built three versions of the Ikkle with 35mm, 30mm and 15mm openings based on the same tea lighter mould.
Results
The first value below is the time to rolling boil in minutes followed by (total burn time). Times are rounded to the nearest half minute:
35mm: 9 (12)
30mm: 9½ (13½)
15mm: n/a (18½)
The 35mm and 30mm produced rolling boils but the 15mm only got to the "Rope of Pearls" stage (~90C) after 13 minutes and held at that until it burned out.
The Ikkles can be crushed/deformed quite easily so I'm going to pack mine in my pot or other hard structure. Their cost, ease of manufacture, fuel efficiency, packability and weight are excellent though.
Looks like the 30mm or 35m will be my go to options for short trips. They'll reduce the wear and tear on my Starlyte, the P&P of which alone would have built me a Giggle of Ikkles