First set of clamps: pipe or heavy-duty F?

[Kesh Ikuma]

Now I have power tool decisions made with the help from the SMC community (thank you so much for those of you posted advices on my other thread!) I've moved on to determine my first set of clamps (other than a few small C clamps that I already own) but quickly became

One of the first things I want (or rather need) to build is a workbench. I'm planning on building my first one out of 2x4's, including laminating bunch of them for its benchtop. So, I figure I need to have long and strong clamps to do this. Obviously, the first thought was to pick up a few of pipe clamp fixtures and 10' 3/4" pipes.

But, I quickly figured out that pipe clamps aren't exactly cheap (for my budget, mind you ) if you get quality clamp fixtures (~$20 total with 3' pipe). Then, today I saw in the promo email from Rockler that they have Jet clamps on sale ("Save up to 40%" sign got me to click that link lol). They got heavy-duty F clamps: 3'x5" for $23 and 4'x3" for $13 (and many others). They seem to be good clamps to get.

So, I'd like to have options on the following to make up my mind:

1. Is there any distinctive advantages of pipe vs. heavy-duty F? (Other than pipe's length flexibility)
2. What is a general rule of thumb for clamp spacing for tabletop lamination? (To figure out how many I need at first)
3. F clamp jaw depth: is it wider the better for the same clamping force spec?

Thanks!!
Kesh