You'll basically want to modify the section just around line 402:
if #MENURES = 1 && ( %quest_type <> FLETCHING || %mintinkertools = N/A )
{
set %quest_type FLETCHING
set %tool UFG
set %toolresource ENK
set %toolresourceamt 3
set %mintinkertools 2
set %maxtinkertools 2
set %mincraftingtools 2
set %maxcraftingtools 4
set %craftitemchain_tool cat_4-nextpage-nextpage-sel_1
set %craftitemchain cat_4-sel_1 ; <---- mod this
set %ressource TLK
set %reshue 1 ; 1-wood, 2-oak, 3-ash, 4-yew, 5-hearwood, 6-bloodwood, 7-frostwood
set %item WOH ; <---- mod this
set %string %QUEST_A_Simple_Bow ; <---- mod this
set %itemamount 10
set %itemresourcecnt 7 ; <---- mod this
set %resamount 120 ; was 70
set %cat 3
set %page 1
set %itemnum 1
set %vendortype bowcrafter$
set %rail1 tobowcrafter
set %rail2 frombowcrafter
set %pakboards 1540
}