So to answer my own question above, I did upgrade my Foobar player setup to the 64 bit Foobar 2000 V2.0. I downloaded the latest version of the SACD input plugin from SourceForge which works for 64 bit applications. This was done to add SACD support to the base Foobar 2000 player. I also use the MathAudio Headphone EQ which plugin which works on 32 and 64 bit applications. The Meier crossfeed plugin available on the Foobar component website does NOT work on the 64 bit version of Foobar.
There is now a VST wrapper plugin available from the Foobar download site which apparently works on both the 32 bit version of Foobar (1.6.14 or later...) as well as the new 64 bit Foobar application. This was downloaded and installed in the DSP chain. I downloaded the Goodhertz Can Opener Studio VST3 crossfeed plugin and opened it within the VST wrapper in the DSP chain and was able to use it to adjust crossfeed parameters for my Sennheiser HD6XX phones. The The MathAudio Headphone EQ was last in the DSP chain to apply my chosen EQ for the headphones. I did not try the VST wrapper on the 32 bit version of Foobar.
This setup works appears to work really nicely. Can Opener Studio has a wide variety of settings that provide great flexibility that allows one to dial in crossfeed for any particular set of headphones. Goodhertz says the goal of this plugin and its variety of adjustments is to mimic the stereo field presented by stereo speakers in rooms with a variety of acoustic parameters. Even based on a short listening session today, it seems to easily outperform the Meier crossfeed plugin I used in the Foobar 32 bit player.
The Goodhertz Can Opener Studio plugin has a 30 day trial period before it must be purchased, Purchase price is $65 US
