ok, just in case anyone here is as ignorant as me in scripting (which I strongly doubt), I'd like to post the modifications of the script if anyone needs changing quest instead of a simple bow, perhaps to train fletching like I did.
First of all, in "setup subs" sections you have to change set %QUEST_A_Simple_Bow 6641256 in:
set %QUEST_Ingenious_Archery_Part_I 18138596
set %QUEST_Ingenious_Archery_Part_II 19715376
set %QUEST_Ingenious_Archery_Part_III 21307596
You obviously know that part I is xbows, II is heavy xbows, III is repeating xbows.
Now just go up and find "Fletching Setup"
Here you can change "set %string %QUEST_A_Simple_Bow" and write the new quest ID (without the numbers) and then in "set %craftitemchain cat_4-sel_1" you change the last number in "2" for xbows, "3" heavies, "5" repeating (cat 4 means the fourth category in fletching crafting menu, which is weapons, sel_"x" is the selection of the menu on the right)
Now change "set %item WOH" and you have to change the item ID: WOH means bows, JSF means xbows, LMH means heavy xbow, PPO is for repeating.
Don't change craftitemchain tool, I thought I had to put the same number of craftitem chain, and then I found my char with a backpack full of mapmaker tools. Basically, this string identifies makes you craft fletching tools.
I know it may not be so useful, but I just wanted to contribute in some way