OK kiddies ---
I jest measured my Brisk and my BM6F and BPMR6F NGK plugs--from seat to top of plug and all plugs are cut off to aprox 1 mm thk on electrode.
there is 3 mm MORE height on NGK -than Brisk
On the ZDZ's the spring in the cap usually allowed this variation -on earlier caps - on later caps when engines came with the NGK-- the Brisk plug barely touched the spring in the top- not good -
So
as long as th plug will allow the cap to compress but not crunch the spring - the various plus all work
in fact -- my ZDZs don't seem to care if I use resistor or non resistor plugs - extended tip or non extended tip and I have never -ever had a hint of ignition interferrence
The Evolution setup is basically the same - EXCEPT the spring take up could be different - so if you make the change pay attention to the above note
If you buy a plug from yer local supplier of spark plugs - just carefull y cut of the top of the electrode to same thickness as your Brisk plug. as for gap - .025 is all you want - you can go a little less
makes no appreciable difference. Don't go more gap tho!