You may have to so some clipping/trimming of her mane/forelock to allow a proper fit. This is when a small, short bridlepath would work well. It isn't just for looks (yes, it would look better), but for SAFETY. The way your bridle is now, because its sitting atop of her hair, she could shake her head and bridle would be gone. Also, it affects the adjustments. Some of us who drive go one step further with some of our known "head shakers" and braid that forelock down and then take it over the top of the crown and braid it down tight to the top of the mane. PITA but it keeps that headshaker from removing the bridle (or halter?, smile!!)...
YES, I understand you train yours differently, but...
another drawing on your bridle - Let's see if I can make sense. The red circle denotes where the noseband would go thru the bridle, behind the bit. That buckle is also where you make adjustments for the bit. Ideally, you would have a keeper there, too, to close up that large, open loop. You can easily do that when you have the adjustments done - using a black shoestring or paracord or electrical tape if you want it to match or anything of your choosing if you're not worried about it matching. A sturdy rubber band works too. Making the lower buckle tighter would make that loop smaller BUT it looks like that would throw off the adjustments of the upper buckle.
You want the blinders to be centered over her eye and that is what the blue circle denotes (adjustment for the blinker). It looks like you can go higher on that (on the right eye?) but that would change the adjustment on the bit end, too...
One think you will find out - for just about every tweak made, there will be a 2nd corresponding tweak to be made. Meaning that if you shorten one strap on one side or part, the other side or part will need to be lengthened.
2nd edit - ADD - I went back to the pic of the full harness you have. GREAT pic, but still couldn't see exactly what I was looking for. The over the head strap is hooked to an overcheck with a "water tie", the flat leather piece, that hooks to the "water hook". The straps look to be stitched to a buckle that is then wider than the opening in the headstall to remove it (my guess - same as I've had in the past). Meaning you probably won't be able to remove it w/o cutting it somewhere...
Sorry.