Light of Dawn vs Word of Glory

For 25 man, 99% of the time, you are better off using LoD because you can almost always hit 6 players/pets with it and at full effectiveness, it beacons more back to the tank than a WoG would. 

Non, crit, a 3 stack LoD hits each target for 6000; a 3 stack WoG for about 15,000. If you can hit 6 targets with LoD, it's 36,000 healing plus 18,000 beacon healing vs a max of 15,000 plus 7,500 beacon healing with WoG. Even if you only care about tank/beacon throughput, LoD is still going to be better. You can expect about 15% lower overall HPS numbers in a 25 man raid using WoG over LoD.

As far as healing tanks and healing your beacon vs having your beacon on the other tank, if your raid can assign healing properly, healing one tank with the other one beaconed is always more HPS. However, it does reduce the output you get on your primary target, so if the healing assignments are scatterbrained (i.e. you are basically keeping a tank up solo without proper support of shields/HoTs, etc), you might be better off beaconing your assignment. The benefit from that is you get HP from using Divine Light on the beacon when you have to and also get the LoD - beacon transfer on your primary assignment. However, whenever I have tried to heal that way, I have found with beacon on a tank, DL is rarely necessary and keep in mind your numbers will be lower than cross beaconing.

A note on Tower of Radiance vs Blessed Life. Honestly, both talents pretty much suck. From 4 hours of raiding tonight for example, Holy Shock was 850 holy power; Tower of Radiance 41 holy power. Blessed Life is fight dependent but generally gives similar results to ToR. I would consider both talents as fairly optional and not be afraid to drop points in either for more useful things. ToR gives the benefit of burst healing on demand since it's controllable, but Blessed Life gives the HP for free without spending 7k+ mana per HP. I'd probably drop Eternal Glory from a 25 man build and possibly look at getting Pursuit of Justice. The benefit of this is you move faster than a run speed enchant allows and also get 50 extra haste in place of that run speed enchant.