I've killed a few elk with a 50# @ 28 PSE Impala. My draw is a full 30", so at my draw I was at 55#.
Elk don't like to bleed externally. Even when you double lung them with a snuffer. They have such a huge chest cavity, that the chest cavity usually has to fill with blood before they start to bleed externally much. The animal is usually dead before this happens. I've never been on an elk blood tracking job, where there was an over abundance of blood, therefore, I feel it doesn't matter if you use a multiple or 2 blade head. If you are using 3 or 4 blade heads because you want a blood trail, there probably isn't going to be much of a blood trail regaurdless. I recomend you stick to a 2 blade head for penatration reasons.
Also keep in mind that, if you don't take out a major artery, BOTH lungs, or the heart with your arrow, your chances of animal recovery are very VERY small. If you single lung an elk, you have a 98% chance of loosing it.
However, if you do manage to take out one of the aformentioned vitals, the elk probably won't go further then 50 to 100 yards before expiring.
I do believe 30 yards is a little far for your set up. If you set in your mind that you will not shoot past 20 yards, it's not that hard to get that close to elk. Patience, patience, patience, patience,.....and oh ya,..wind in your face,... you won't have a problem. If you hunt thick cover you have no choice but to get close.
Don't risk it, man. It's not worth it. Like Dave2old said,... you can get lucky and kill an elk at 30 yards with your set up. But,... If you're depending on luck for your setup to be efficent, you are better off staying home.
That being said, I would love to see you have a wonderfull time.
Todd