When you do get around to trying it, if it doesn't seem possible, just bear in mind that everything on a boat is synergistic.
"IF" the hull design is right
"IF" the sail plan is right
"IF" the right sails are up
"IF" the mast isn't canted too far forward or aft
"IF" the sails aren't blown out
There's a whole long list of stuff that can make balance difficult, even if the boat is capable of it. On the bright side, when you CAN steer the boat under sail alone, and you can leave the rudder centered, you are going faster (without the rudder being a speed brake) and you KNOW you've got it trimmed right. Don't be surprised if it takes a while to get there.