I would add the flaps but I would give myself some method of adjusting their total throw - Start with a small amount and add throw after test flying. If you don't like them, you can always connect them to a non-moving point.
I suspect that with that real low wing, there will be a lot of nose-down pitching added as the flap deflection goes up -
Start with lots of altitude and at low throttle and realize that if you are very nose-heavy, it MAY be difficult to keep the nose level when the flaps deploy.
Of course, it may also just bore straight ahead or balloon up when they drop but give yourself the wiggle room.