Penetration and cast level. Also, blood vengeance.

[UncleYee]

I seek the wisdom of the forums. I have two questions. First, is the spell penetration bonus you get from an item the same as the bonus you get from having a higher level? For ex, are these equally hard to resist?

B4 mage casts hellbind heart
B3 mage with spell forcus casts hellbind heart
B2 mage with eye of void casts hellbind heart

I just got a little less lazy and looked up magic in the manual (p.86), so now I see that what I'm asking is: is the penetration bonus (from items) added to the caster's roll BEFORE it gets divided by 2 (like the spell level bonus) or AFTER?

Second, does either or both spell penetration bonus and higher level make for a more effective (each reflection less likely to be resisted) blood vengeance?