DJ. Of course there are many ways to do this, and every thread finds at least 3 variations.
My "standard" boiler lagging comprises the following:
Cover the boiler metal with aluminium foil, shiny side out. I use spray adhesive to stick it to the boiler. Cover the foil with corrugated cardboard - again with some adhesive.
Cover the cardboard with another layer of foil, shiny side in.
You have now made something like a thermos flask and stopped 99% of the radiant heat losses, as well as a lot of conductive losses.
Then clad with the wood planks as a dress finish.
The are many insulating fabrics, and one of the best is wool, or cotton or a modern silica based stuff. The modern stuff isn't any better as thermal insulation, but takes high temperature better.
I use corrugated cardboard as so far my oldest boiler is 25 years old and it is still OK. It doesn't char at the temperatures of the boiler sides. Before silica fabrics became available, cotton flannel was common lagging fabric. Natural insulation - wool - is very good, as sheep wear it to keep warm.
I have also used a lot of balsa wood, as it is one of the most insulating of woods. It needs a stain and varnish to improve the looks.
If you want a design of burner I'll do a drawing, but there are many that work. If you don't follow a design that works, you can have a burner with hot and cold spots, that can flash-back, crack the ceramic, etc. I have experienced all the failures in 20 years! ( BUT I think I am doing it right now).
I reckon you need 1/2" each for a mixing chamber (plenum) beneath the ceramic, the ceramic itself, and flame space. Very tight, but the minimum I have used. Using Butane: A 0.25mm jet (no.8) with 6mm, 1/4" inlet tube, 2 inches as mixer tube, may be OK or but I think it should take a 0.30mm jet (no.12) with 8mm inlet tube as I think the flues are well capable of taking the exhaust. The air holes need to have 1.25 x the CSA of the mixer tube. Face of jet located at the leading edge of the air-holes. Put a drill in an air-hole and set jet to the drill.
Anything more, just ask.
Cheers,
K2