I note that you did not answer about sandblasting the sealing surface/mating surface..

Unfortunately if the cylinder head face was sand blasted, premature gasket failure is a common result.

Most sandblasting aggregate is too aggressive for the cylinder head, and will remove metal in uneven patterns from the sealing surface/mating surface = ruin the smooth even surface = cause leaks.

Permissible roughness of parting surface
Lengthwise 0.08 mm
Crosswise 0.0 mm

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Here is more technical data on the topic.
cylinder head surface finish premature gasket failure:

http://www.aagaskets.com.au/PDF/AA004%20Distortion%20and%20Surface%20Finish.pdf

cylinder head surface finish is critical to gasket seal

http://www.engineaustralia.com.au/~engine/sites/default/files/SB024.pdf

Cylinder Head Resurfacing -Surface Finish & Gasket Sealing Theory : MA,CT,RI,VT,NH,ME,NY,NJ

http://aftermarket.federalmogul.com/en-US/Technical/Documents/How%20To%20Prevent%20Head%20Gasket%20Failure%20-%20Improper%20Surface%20Finsh.pdf

http://aftermarket.federalmogul.com/en-US/Technical/Documents/Surface%20Flatness%20and%20Finish.pdf

http://www.reinz.com/pictures/39-00331-00_PI_5_MLS-ND-e-low.pdf

Common Mistakes to Avoid When Resurfacing Cylinder Heads & Blocks - Engine Builder Magazine

https://www.google.com/search?q=cylinder+head+surface+finish+gasket+failure&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-USfficial&client=firefox-a

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