Demz I had a quick go..
I was surprised you were using those barriers. I'm familiar with them!
Made me want to try.
Here's what seems likely, just a few attempts though I could be wrong.
I did a smith, not a long one just a quick kiss, this kept me sideways.
So in theory you could maybe do a backwards feeble as to not lean toward the top of barrier thus leaning into it instead. I don't think feebles are doable for this reason. I also got a pretty clean 50-50 before flopping to my face.
So some things I would try;
Pump up it, obviously you got that part down.
Powerslide into the grind.
Play with grind distance, maybe try a couple smith grinds instead.
As for arms and all that.. Good luck. Not anything I've ever studied in the games. Did this infront of 2nd and navy, might be a good place to start. Text wall hell!!
https://youtube.com/watch?v=yS_WRpQgA3E