Centering ring and packing

[Bustard]

Good Morning all,

My setup i just finished:
4" copper column made up of 4 x 600 mm sections
LM head with reducer and T trap - 1/2" needle valve
100L SS boiler fitted with 2 x 3kw 220 V ULWD elements controlled by SCR voltage regulator
Packing will be copper and stainless steel knitted mesh

Will be used for neutral spirits and boiler charged with stripped product at 30% abv

Calculations on the parent site indicate that i can have a packed section of 2000 mm running at 4500 W and a bit more if needed with very little reflux.

My question is the following:

Can i pack each section with 500 mm height of mesh leave a 100 mm space with a centering ring above? Or should there be less of a void space?
When insulating the column should i insulate the entire column or leave the void spaces bare?

Any input appreciated.

B