Glad to see you back ! Ok reading what you have posted. I think you need to google FJ parts You will find APS and they have a lot of pictures. West Marine also has a lot of parts.
You need to be looking at the bow plate and forestay adjuster I think. I will assume you have a bow plate and it may have three or so holes in it ? This is where you are hooking your forestay with a carabiner. I will not say this is not right because sailing is about learning to make the boat fit you and your needs. It is not the normal way to do it. I will also guess it is not class legal. My boat has an adjuster with a pin in it that will not fall out.
Lets talk about class and one design. APS that has parts for the Vanguard FJ > I have a Southern Ohio sail craft FJ . A manufacturer may pay for the rights to build and sell all the FJ boats that they can. They make them to one design and the class rules. This means all the boats are (almost the same
wikapidea has history for the FJ, University MD, New Bren High School these places are good for your web searches.
about your mast place it in the middle for now. I like to have some rack or have it leaning back in high winds and more up right in light air The rig tension I like is tighter in a good breeze and less so in light air.
Next I need to tell you on my 1967 FJ when I capsize I can with effort right it. I am 180 lbs 6 ft If I turtle it is a lot of work to get it up right. If I am in 2 foot waves I can not get it bailed out the waves will wash over the deck and the center board will be below the water line. The boat is swamped until I can get her to the shore. What I am trying to say is have a plan. That said the FJ is a nice boat and if you put the rail in the water you will get buckets in the boat have a huge loss in speed They stay up right for most normal use. They are stable and sail best when you can keep them kind of flat.
Kind Regards, Lou