Looks like you get the hang of it, and have determination ! And yeah everybody have to pass throught this you def not alone , hopefully freeborders are often very happy to share their experience (and it's great , we all have a different one ) :) (I think it's because we are a minority ^^few people ride ,and freebord is not really a mass known riding product, so we can't really talk a lot about our passion in daily life !)
About your first post, from my experience:
1/when I start freebording i have 10 weeks of snowbarding (1 weeks per year during 10 years) and I only ride regular (don't even think about taking the time to learn goofy, one week is too damn short ^^)
So when I buy my freebord I decide to make the test and i learn to ride goofy (after take 1/2 good week to make the link with my snowboard level, when it comes it's like a "click " in your brain ) because i have no lift ticket to buy ,i can have a training on a 1% steep/no cars spot behind my suburban house.
I was so happy when i go back on the snowboard and realize it was even more easy !
If think the reason is when you want to go straight on your snowboard you have the totality of the deck in contact with the ground, but in freebord you just have the Two center wheel. It's kind of the same balance skillz but way more precision is needed on the freebord, so i think that's why its easier for a freeborder to learn snowboard , than for a snowboarder to learn freebord (at least at the beginning ).
2/ about size of the i'm also 1,75cm and i start with a 83cm, now i'm on a 85cm;
Good luck and be carefull to you elbow (just know is not a bad thing to be forced by an injury to learn with caution , that will give you safe reflex !)