Driveshaft out of phase?

[Sharkdance]

Greetings,

Have a 70 F250 2WD C6/Dana60 with a two piece driveshaft.
When I removed the driveshaft I marked the splines so that I could put them back together in the same position. Apparently they will fit back together in any position because the splines have no index. (their the same all the way around)
Anyway, I marked them with soapstone and since removing them the marks have rubbed off.
Ive been told that if their not re-installed in the same position that the two driveshafts will be "out of phase" and will be out of balance.

My question is:
Is there any way to figure out how to re-phase them without taking them to a driveshaft machine shop?
If I just put them back together how bad can the out of balance situation be?
Am I worrying too much and is this "out of phase" story even true?

[FORDification]

Just get the U-joints aligned in the same plane when installed, like this:

http://fordification.com/forum/files/phasing.jpg

Notice how the caps on each u-joint is aligned with each other, instead of one being (for example) pointing towards 2-o'clock and another a 4-o'clock. Both should be at the 12/3/6/9-o'clock position.

[dcbullet]

I had to line them up correctly when I installed a new different lenght driveshaft after I switched rear ends. I had no problem following the directions out of the shop manual so if I can do it anybody can.

I've had no vibration problems at all.

[Sharkdance]

Thanks Keith and dcbullet, I will follow the info posted.

I have a set of shop manuals but didnt even look. Just went off of the story I was told and semi-panicked when I realised my marks were gone.

Thanks for the quick and acurate answers.
Yet another reason I love this place.