Though dCore supports *.gz initrd files as a part of a remaster in /tmp/builtin, remasters of the main initrd are a last resort to me as that inhibits keeping with updates. If you have an ntfs-3g.gz, then you can place it the chosen /boot directory and specify it as another initrd in the boot loader, below is what I used with grub2 to have ntfs-3g available as if it were in the main dCore-*.gz image, and hopefully similar works with grub4dos:
insmod ext2
set root='(hd0,msdos7)'
linux /boot/vmlinuz-wily quiet max_loop=256 tce=sda7/tceimport-wily showapps user=jason nozswap desktop=startlxde
initrd /boot/dCore-wily.gz /boot/ntfs-3g.gz
In fact, I a have created an sce2gz tool that is available as an extension that can create a *.gz out of an SCE in the SCE directory or one of one's choosing. Works much like sce-load. This is mainly to support ntfs-3g and perhaps wireless, but should work in any case. Startup scripts in the extra *.gz are processed as usual and added to the list of installed packages. It is assumed sce2gz is used to create the extra initrd's, convert raw Debian packages at your own risk.
Please try booting with the extra initrd and let me know how it goes.