KPro w/ return fuel & aftermarket FPR

[KSeries4Life]

KManager 4.1.4.0
02-04 RSX Type S PRB ECU
NA K24/K20 swapped 2004 S2000
Magnus Sheet Metal K-Series Intake Manifold
90mm KTuned TB
Stock return fuel system w/ KTuned FPR
Injector Dynamics 725
E85 fuel

Hello,

Looked all around and couldn't find anything on this topic. I'm currently attempting to tune my injector dead times and have been looking into rail pressure vs effective pressure. Manufactures use a variety of ways to compensate fueling based on the effect manifold vacuum/pressure has on effective pressure. Pre 06 S2000s look to be using a vacuum line to reference it's FPR. K-Series vehicles being return-less, modulate the fuel pump to keep a constant rail pressure and the ECU using calculations to alter dead times. Am i correct on that last on? Is this what test pressure is vs current pressure as seen in FlashPro?

If I'm correct that K-Series ECUs use manifold pressure to compensate for the change in effective fuel pressure, should I keep my FPR's vacuum line disconnected? I'm wanting to know which would work better with my setup considering K-Pro is available for pre 06 S2000s that use a vacuum line referenced FPR. Then again, there may be something altered in the S2000 version of KPro to work better with it's fuel system. If no vacuum line to the FPR is needed, should stock RSX fuel pressure (reading it's 47-54 psi) be use with K-Pro? There doesn't seem to be a way to set the test and current fuel pressure values like there are in FlashPro.

[Hondata]

The short answer is either way works.
You can keep the fuel pressure constant above manifold pressure (pre 06), or have a return less system (06 onwards). The only difference is that the shape of the resulting tables will be a little different, with the return less system having lower table values in the lower columns.
None of the Honda ECUs regulate fuel pressure (exception: RDX).
For forced induction a return system is recommended.