Fancy Me, your horse is quite pretty
and you've got some great and appropriate equipment on her but may I make a suggestion? Try running the lines through the lowest loops down on her sides as this helps prevent her from spinning to face you and allows you to keep better contact on the reins while she gets through the inevitable green horse sillies. Move back to the highest rings right before you switch to the driving saddle and actually get her ready to hitch. The higher the rings = the more advanced the horse. Using lower rings lets you use the rein to help hold her hip on the circle and teach her to bend. You might also move the surcingle back just a little bit.
I want to post some of my newer combined driving pictures but don't have them loaded yet so I'll settle for the only recent photo I do have online.
Here are two show pictures from July:
Both of those were taken at the Beavercreek CDE during the cones section where cantering is allowed.
Leia