OK, for those of you experienced folks: I've seen the type of caulking in this link used before:

http://store.hamiltonmarine.com/browse.cfm/4,6511.htm

But, haven't seen this in use:

http://store.hamiltonmarine.com/browse.cfm/4,6512.htm

What's the real difference--when is the second one used? Thinner seams? Any difference in performance or technique?

Getting ready to caulk...so buying caulking...got the irons, making a few too, but don't yet have anything better than a couple ordinary wood mallets...

Thanks!