How do you
You need something else between the Seniorita and the Ultimate Bipe![img]i/expressions/face-icon-small-shocked.gif[/img]
That biplane will react MUCH faster to small control movments than the Seniorita could ever hope to maneuver at full deflection. Also, the biplanes tend to have a very high sink rate when the engine dies.
Adding the ailerons to the Seniorita isn't a bad idea. Just adding on full san strip ailerons appx 1 inch wide will make a big difference. It sill not properly prepare you for the biplane though...
Build a Four-Star or something similar for a second plane. Get used to the higher response rate of that... then you have a hope of being able to handle the biplane.
When building the biplane... get an incidence meter to set the wing angles up. a very minor deviation in wing alignment can mean a tremendous trim problem.