I would like to propose to use this little addon: GroupCalendar
I don't know pretty much thing about it, but I found it very useful & interesting - if this works good, without errors, it will be much easier to make the raid signs (for the lazy ones); it has only one minus point in my opinion - you have to be logged in the game to sign for raids - but gives a better overwiev about the signers.
I would like to hear other persons opinion about this.

Be good, may all your wished loots to drop

I think it would be better than the forum signing. Easy to tell which classes are full or needed. Should be tried out at least

I just got the addon...love it! ...everyone should get it...at least for test....it's rly easy

it possible to calibrate them with others that have the same addon in the guild, but for that we need the channel and password. Maybe the officers can create the channel and post it here or in guild info?