Common grace and paradox

I recently linked toDavid Engelsma's review of a new biography about Gordon Clark:

https://douglasdouma.wordpress.com/2017/03/03/david-engelsma-reviews-the-presbyterian-philosopher/

While I agree with some of what Engelsma says, there are times when his bias clouds his judgment:

i) The CRC has been on the skids for decades, as has Calvin College and Seminary. 

However, at the time of the Clark Controversy, I believe Louis Berkhof was the nemesis of Herman Hoeksema. It would be absurd to suggest that Berkhof doesn't represent authentic Reformed theology. Moreover, the CRC continued to have orthodox representation in later figures like Anthony Hoekema. 

ii) In addition, the OPC, which was founded over 80 years ago, hasn't followed the downward spiral of the CRC. To the contrary, it's maintained an impressive degree of theological stability and conservativism despite changing hands so often.

iii) Although liberals in the OT department at Westminster Seminary were in danger of adulterating the orthodox stance of the seminary, that trend was recently reversed under new administration, and the reversal enjoyed significant support from other departments of the seminary. So Engelsma's predictive trajectory is unreliable. 

iv) Perhaps owing to his age, Engelsma's attack on theological paradox is rather dated. If you're going to attack the principle of theological paradox, a better foil would be the more recent and rigorous formulations by James Anderson. 

I myself don't find Christian theology paradoxical, although it inevitably has dimensions that exceed human comprehension. 

v) Engelsma seems to be oblivious to the fact that Clark's theology became increasingly eccentric in his later years. Flirtations with idealism and occasionalism. Dubious formulations of the Trinity and the hypostatic union. A Sandemanian definition of saving faith. Necessitarianism regarding the creation of the world. 

Moreover, some of these aberrations represent the outworking of his disdain for sense knowledge. 

vi) He fails to mention that Norman Shepherd's views got him fired from Westminster. 

vii) He doesn't bother to explain how the Federal Vision is the logical outworking of theological paradox and/or common grace. 

Invariably, indeed necessarily, the truth being, in fact, rigorously logical, the doctrine of universal, ineffectual grace in the “paradox” drives out the doctrine of particular, sovereign grace.

i) Common grace is not ineffectual. Rather, it serves the purpose for which God intended it.

ii) Common grace is something of a catch-all category, so assessing the claim depends on which elements are included in the package. I prefer the position of Paul Helm and William Young to John Murray in this respect. 

iii) Since, moreover, it denotes something different from saving grace, it's misleading and confusing to use the same designation ("grace") for both. But, unfortunately, that's the standard label.  

Under the influence of Westminster Seminary, the OPC has approved a covenant theology that expressly denies all the doctrines of grace of the Westminster Standards, including justification by faith alone, with special reference to the children of believers.

I'd like to see documentation for that sweeping allegation.