Anyway, finance plan and crafting plan for Tenebrynn and me: I get the nexus fixed, purchase a scroll of secret page and erase (reason later if it isn't immediately obvious), scribe secret page into my spellbook, and craft my blessed book. Then I scribe all spells, including erase, into the blessed book (yay for freedom from the 100 gp/page cost). 
Tenebrynn can then borrow either my old spellbook or my blessed book to prepare the spell for his bookcrafting (he can't really fail the Spellcraft check). I 
erase the sparkstrike from my old spellbook, so I can safely sell it.
Tenebrynn does not need to purchase scrolls of dimension door 
or secret page, which he can copy from me (or, if he prepared dimension door three times, from his memory 
in that case). If Tenebrynn purchases a fox's cunning then, they can craft a headband of intellect then, and Ashnar has enough resources to research two or three spells on his own (perhaps more if Tenebrynn is capable/willing to help). That should work out something like this:
	
	
	
		Code:
	
	
		+15,000 gp?					Share
-    40 gp					Ivory plaque
-   750 gp	-  40 XP			Fixing Necromantic Nexus
-   400 gp					Purchase scrolls of secret page and erase
-   300 gp					Scribe secret page to spellbook
- 6,250 gp	- 500 XP	-1250 Craft	Create blessed book
						Scribe spells, including erase, into blessed book
						[i]Erase[/i] Ashar's sparkstrike from old spellbook.
[s]						Lend blessed book or spellbook to Tenebrynn for his crafting efforts[/s]
+ 3,500 gp					Sell old spellbook (70 pages scribes without sparkstrike)
- 2,000 gp	- 160 XP	- 400 Craft	Create headband of intellect +2
- X,000 gp			- X00 Craft	Spell research
	 
 Any glaring errors with that plan that I shouldn't have overlooked?
Yep, saw it after rereading the borrowing passage.