I assume you wanna use Cubase x64 so very easy :
install your x86 plugin in : program files x86/steinberg/vstplugins
& your x64 in : program/steinberg/vstplugins
point cubase to see your vstplugins folders in “plugin info”
your vst3 presets must be : "user / documents / vst preset / rescan your mediabay et voila
Home Studio 87 is correct; if running 64-bit Cubase, you can just update Cubase’s VST 2.4 plugin paths to look in both Program Files (x86) and Program Files- Cubase appears to be smart enough to use the 64-bit version if both 32-bit and 64-bit are found in the search paths.
Please just keep in mind that not all 32-bit plugins will work properly on 64-bit Cubase without some 3rd-party help (some folks use jbridge to make 32-bit plugins work better on 64-bit DAWs).
It’s also worth noting that you can have both 32-bit Cubase (in Program Files (x86)) and 64-bit Cubase (in Program Files) installed on the same system and can switch between them freely. The 32-bit version works just fine on 64-bit Windows, and should be perfectly adequate for most users unless you’re dealing with very large projects or huge amounts of samples/audio.
I have enough 32-bit-only plugins that don’t work right under Cubase 64-bit that I use 32-bit exclusively, and have not yet needed to experiment with jbridge.