Sorry, but the LDC-Module always uses 7 bits from a single port. To change that, you'll have to modify the lcd-software.
Generally speaking the low cost character modules come in two
flavors, with and w/o controller on them. The ones with, industry
standard is 44780 Hitach (Renesas) or compatible controller. If
you examine datasheet writing your own APIs is not so daunting.
The command set for these are very simple.
I would advise control signals on one port, data on another. Don't
split up control signals, should result in clean code.
I attached one 44780 datasheet for you, there are several versions,
but seem largley compatible at command level.
HD44780.pdf 322.1 K