Gunna attempt to give myself the Eternal Ferrystone via the save editor now. Will post when finished so that we have an easy explanation on how to do it!
Edit: Success! It was pretty easy for me to get the Eternal Ferrystone (One of the few things I disliked, not being able to move around quickly).
I used the search function in the editor to find "array name="mItem" ", replaced the ID of whatever the item was that was there (I have no clue what it was, really) with the ID for the Ferrystone, and made sure that the data.mDay1/data.mDay2/data.mDay3 values matched that of data.mNum.
It's simple, but it can seem confusing. I do not know about editing in your own item into a blank space yet, though. If anybody knows how to do that quickly, feel free to throw a post or a link!
Thanks again for this awesome trainer and editor!
[Edited by timmage, 1/16/2016 1:23:57 AM]
Second edit! I think I have figured out what the value is! This might also come in handy in some trainer updates, I'm not sure.
I believe that piece of information is what page of your inventory the item is is. I would like to get some additional confirmation on this, of course, so if anybody is willing to test it themselves, that would be awesome.
When I say page, I'm referring to Curatives, Tools, Materials, Special, Other, etc. Those pages.
I attempted to give myself some Bitterblack Weapon Lv. 3s, and failed on my original attempt. I then used the wiki to confirm what section/page they came under in the inventory, and found them to fall under Other. I put a Seeker's Token in my storage, went into the editor, and changed the ID on it, and nothing else, and it worked to turn it into the weapons.
Since Array's start at 0, it makes sense for that little piece of memory to dictate what part of the inventory it goes in, and could also be the cause of some crashes and/or instability in save files, if, say, you attempt to equip Greenwarish as a weapon.
Thanks to anybody that confirms this!
[Edited by timmage, 1/16/2016 5:16:07 AM]