"Blueprinting" VW heads

Hi Volks,
I'm aware of the importance of keeping head chamber volume equal
across all the 4 cylinders as well as the benefits of a port and
polish job. But I am wondering about the techniques of cleaning up
the exterior fin area of the stock cast VW cylinder head.
Specifically, I would like to clean up the casting imperfections
(casting flash?) between each of the fins.

I look "down" into the head fins (from the perspective of the air
coming from the fan shroud) and I see places where it would seem that
the VW engineers intended for air to blow through. But deep in those
places are blockages by random "flash" (like the plastic flashing have
to trim away when you build a model airplane or such). My first
impulse was to get a small flat-headed screwdriver and rubber
mallet...but that didn't seem wise. What tool should I use to get
deep in there and clear out those places between the fins.

I know it seems anal but I am trying to blueprint the cooling design
of my 1776cc Type 1 engine (with Webcam 163 camshaft) so that I may
safely run a higher CR (9.2:1) while running pump (Premium) gas in
California. I am running the late Doghouse fanshroud with all cooling
flaps and all the other various cooling tin that everyone forgets
about.

I am also exploring getting heat barrier coatings applied to the
head combustion chamber by these guys:
http://www.replikamaschinen.com/ If the cost of getting those
coatings done is less than $300, I am certainly going for it.

Anyways, thanks for any advice on head fin cleanup as well as
highest CR for my engine.

Regards,
Geoffe Elias

'74 Super Beetle