I can't help you with the compression problem, but I read the article, and I see a lot of beautiful fabrication, but little or no engineering content. I see this a lot in the hotrod and restorod world.

Long tube headers make no sense on a supercharged engine because at WOT inlet pressure is always greater than exhaust pressure throughout the exhaust cycle. Unless boost is only a few psi, wave dynamics from long tube headers won't create enough rarafaction anytime during the exhaust cycle to be of any benefit. The best exhaust system is a set of streamlined manifolds, and the OE exhaust manifolds would likely work better, especially if ported.

Similarly, long inlet runners are of no use and actually cost power because of increased friction. Long inlet runners can enhance VE on a naturally aspirated engine due to inertia pressure as the valve is closing, but does little good on a boosted engine because inlet pressure is already high due to the supercharger.

The best models for supercharged engines are the engines used by American Funny and Top Fuel cars. An adapter is used to connect the Roots blower to the cylinder heads, which yields the shortest possible inlet tract.

Likewise, on the exhaust side, individual exhaust pipes are just long enough to clear exhaust gas from the chassis.

Valve timing for a boosted engine also needs to be different than typical for a NA engine. Boosted engines should have little overlap, again, because inlet pressure is greater than exhaust pressure, so the fresh charge is not short circuited directly out the exhaust, and the split overlap point should be well after TDC. Hold the exhaust valve open longer than a NA engine to avoid cylinder pressure buildup late in the exhaust stroke, and it may need to be opened relatively early to achieve blowdown by BDC. Then open the inlet valve late and close it late.

VE is a function of high boost pressure and short, low friction inlet runners, and on the exhaust side, minimum plumbing is used to keep friction as low as possible commensurate with safely routing exhaust clear of the chassis and driver.

The best way to work out a custom engine configuration is with the various inexpensive engine simulation programs. The one I perfer for both racing and road engines is Engine Analyzer. I used EA to design a new camshaft for sixties/seventies base engine Corvettes. Along with massaged heads this camshaft yields OE idle behavior, but 20-30 percent more top end power and another 500-1000 useable revs without the loss of any low end torque, so it maintains the smooth idle and stump-pulling low-end torque of the base engine, while making about the same top end power and revs as the Special High Performance hydraulic and mechanical lifter camshafts that kill low end torque and cause a rough idle due to the high overlap.

Duke