Another newbie question : Dovetail Jig

This may be a no-brainer or awnsered elsewhere but here ir goes. I have that Porter Cable 12” machine and while it does say in there that I can dovetail boards as wide as I need by clamping the template to another board and indexing off the last dovetail. It seems like a pain and I have a concieved project coming out that will require 24” through dovetails. Couldn’t I dovetail two or boards 12” wide on the end and then glue the long grain sides together to make around 24”, I know that the boards will need to be carefully trimmed to line up the dovetail to avoid an out of place extra wide dovetail.

Warning RANT approaching:
Now on to a little venting – is anybody aware of or used the 5” hook and loop microplane sanding discs? I bought two sets from Rockler one medium and one fine. I was less then impressed, I used the fine which is to equal about 120 – yeah right, worse then 80. It took longer to sand out the damage with 120 then I had used the microplanes. They leave a surface akin to a belt sander only more random I guess plus if you bump into another board with the edge it actually sliced into it close to an 1/8” deep. I know I shouldn’t be, but I am a little disgruntled by Rockler for carrying such bunk (My opinion, all), but I still love them and they did just refund my shipping and handling since they offered their free shipping offer while my order was still in transit. I am not going to return them or anything I figure buyer beware but I will take the products the Rockler sells with a grain of salt from this point forward. Thanks for listening rant off.

-- RickM