Hey Spastic! First of all, good for you for getting out there and taking the steps to accomplish your goals.
I wouldn't be too "worried" about your form and your position while being out there, "where's my hip angle, where's my shoulders, where's my hands, where's my this and that" - phtphthpt. I would be more focused on remaining over your horses center of gravity, and your solidity in your lower leg.
Get your iron in the correct spot, allow your heels to absorb your bodies weight and to anchor you, and re-position your calf placement. Right now you have way to open of a toe angle, close it a bit where your placement is right inbewteen the back of your calf and the inner of your calf.
Get your legs at that girth, and wrap them around. Remember, you are not ontop of your horse, you are around him - as George Morris teaches.
When you are going over the fence, remember that your horse is the one who closes the angles, not you. Stop focusing on the fence, focus on your horse. Allow the fence to just happen. You don't ride to the fence, the fence comes to you.
Work on closing your knee angle, sinking into your heels and pushing your seat back.
Your best friend while doing xc will be your 2 point position, work on this over and over and over and over. You should beable to sit in the saddle and get out of it regardless of what gait you are doing. You should also beable to stay up in it, longer than your xc course time would be. *For example.....BN is usually 5:50, so you should beable to comfortably stay in your functional two point position longer than that*
Seat tucked under you, core activated, lower back strait, hovering just over your tack. Lower leg stuck like glue. Chest opened as though you are lifting your heart, and with every upstride your horse makes, your legs are saying "come up to me" lifting his back up into your seat.
You need to work on your half halts, while up in your 2 point. Where your body tenses up, core tightens, hands come into your belly button and release. You bring your horse under you during this, and then when you get the desired rhythm and balance, you release. This is important when you are 5 strides out from your fence.
So, all you really need to do, is solidify that lower leg, and your core. Find your center of balance. FIND your sweet spot and stick with it.
I sit 5 strides from the fence. The trick is to feel your horse. Stop focusing on the fence, stop thinking about the fence and start riding your horse. Ignore the rest - the most important is what is under you, your partner...NOT what is infront of you. If you are solid in your tack, you can ride anything. 5 strides out, sit, half halt, release and remain solid. Ride your horses rhythm and the fence will just happen. Allow your horse to do his job, while you do yours - staying balanced and out of his way.
Look at those Upper Level Eventers...do they look pretty? No..but you can be darn tootin' sure, that they are solid and aren't going to go anywhere. They do not hinder their horse, they aid their horse. Find your balance, find your anchor/solidity.
The rest will just happen.
Let go of his face. You are too much in his front end. You aren't allowing him to do his job.
Find your canter, a nice cadence, impulsion gait. You want that pop and that spark in his movement. 2 point - between the fences.....feel it. Ba dum, ba dum, ba dum, ba dum. You see your fence, you line him up. Half Halt, rock him back under you, and let go. 5 strides out, sit, put him in check *come back under me* and then release. Allow him to do his job.
1) Work on that lower leg. Solidify it. Make it strong. Correct calf placement. Wrap yourself around your horse.
2) Functional two point. Solidify this. Strengthen that core, use your body in unison. YOu should beable to let him go out full force and bring him back under you in the snap of a finger - all using your body. Tighten, release. Tighten, release.
Work on your Coffin Canter. A strong, impulsive canter, where you are almost moving on the spot. Collect that energy and keep it under you - then let it go - bring it back - let it go - bring it back - let it go. IMPORTANT factor to have out on the XC course. You need to beable to open up your horse and trust him, and beable to bring him back under you in the snap of a finger.
THIS is what your Coach should of been working with you while out there. It's not about going over the fence, it is what you are doing inbetween them, that makes that fence quality.