Decks, Patios, Porches and Docks - Two Q's on deck building

I'm building a PT deck that has 5 sets of support beams, each made of 2 - 2x10s nailed together. I've read that I should caulk the seam between the two 2x10s so water doesn't get inbetween. How important is this, and is it effective? Problem is, I forgot to do this, and I now have all the joists up. :-( I've also read I should have put preservative on the end grains of all the posts... another thing I didn't do. Again - is this important?

I figure if it's really important/needed, I can run a bead along the seams between the joists at least.

Also I bought milled rails for the railings as I used them on a previous deck, but on that deck, I used exterior screws and angled screwed them in. Wasn't overly thrilled with the look.

Is there any standard method used to attach milled railings to the posts? Wondering if angle screwing them using #8 screws is the way it's done by others.

Guess this is 3 Qs.... :-)

I've never heard of caulking in between 2x's. In an interior application....sure. A liquid nails type of agent acts to bond the two together to strenghen more into one. However, outside, with P.T.? P.T. is loaded with all types of preservatives/chemicals and therefore is bought "wet". It takes a little time for the wood to dry out, but is in an outdoor condition, hence it will get wet over and over and over again. So the theory of caulking to keep water out doesn't seem to make a whole lot of sense.
As far as attaching your railings to the posts, there are a few off the top of my head (and I'm sure more from other posters)
If you don't like screws angled in, then you could try small angle brackets or counter sink some longer timerlocks from the other side of the post and cut plugs to fit. (the plugs will shrink with the drying out of the P.T., so use adhesive)