MP5 is garbage. You get more mana back from int with BoK if you can assume an 80% uptime on replenishment. That's not a bad assumption considering hunters, ret pallies, and destro locks all provide it (and frost mages, but who raids as frost?). Most holy pallies are actually upset when they see mp5 on gear.

Not to jump on the bandwagon.. but this should of screamed at you before you posted.

http://theholylight.wordpress.com/2007/07/10/paladin-healing/

What stands out in the above URL.. Should ring some bells, imo.

http://elitistjerks.com/f76/t55577-holy_paladin_guide_3_1_a/ is the only thing you need until 3.2 comes out.  Every trick and technique is covered there in great detail, including the proper descriptions of Sacred Shield and Beacon of Light. EJ is your bible. You think WE'RE hard on proper theorycraft, THEY ban people for mispelling :)

#1. Now, I'm not sure if you realized this or not, but the old mechanics of downranking spells has been tossed out. You need to double check your mana costs of downranking. A Rank 7-9 of FoL cost 307 mana while a rank 1-6 all cost 351 mana. A Rank 11-13 of HL cost 1161, while ranks 1-10 cost 1380. You don't "save" any mana by downranking 2 ranks of your spells while taking a larger pentaly by downranking. And downranking isn't just regulated to just healing spells: every spell in the game has a mana pentaly for using a downranked version of it instead of you using the max rank of the spell

#2. I think you are confusing the mechanics of Beacon of Light and the glyph of Holy light, and quite possibly not understanding the usage of Beacon of light. Lets start off with the glyph of holy light: Your holy light grants 10% of what you heal to 5 friendly targets that are within 8 yards of the inital target. Now to the mechanics of Beacon of light: "The target becomes a Beacon of Light to all targets within a 40 yard radius.  Any heals you cast on those targets will also heal the Beacon for 100% of the amount healed." That means if you beacon the tank and heal yourself while you have full health, your beacon (your tank) gets zero heals. In your example of a lock that has spammed life tap, you are better off beaconing your tank, and healing the lock, not the other way around. Look it this way for example: a tank takes about 3-4k damage roughly every 2 seconds in a heroic, and a warlock lifetaps from 23k HP to about 8k (a differnce of 15k hp loss). Now, if you beacon the tank and happen to crit a holy light for 15k: congratulations, you have healed 2 people to full HP in 1.5 seconds. However... if you did the other way around by beaconing the warlock, well.... you're going to take atleast a good 8 seconds untill you heal both of them, as overhealing doesn't get sent to your beacon's target.

P.S. The blog that you posted as the first link has outdated information from 2007. This goes back to #1 and what has happened to downranking. http://forums.worldofwarcraft.com/thread.html?topicId=8974837994&pageNo=... should explain where and went downranking went the way of the dodo.

edit: http://theholylight.wordpress.com/2008/08/14/down-goes-downranking/ Same author, dated 2008 during the Wotlk Beta. You should have seen this if you bothered to read the whole blog.

Facepalm 2