All good heads.
I might suggest looking at the CT250 Flight Control instead of the Professional - more coin, but just a fantastic head.
Depending on what you're using your PW and GW/AW for will dictate whether they're M series or KE4's. If you're using them for full swing shots all or most of the time, get the KE4's. If you're using them for half swings and touch shots most of the time, match them to your wedges. The only difference between the KE4's and the KE4 Tours is offset and a little sole width.
I love the dark finish on the M series - and it's a good wedge to boot.
Now, SMT can offer all the same stuff, but your driver will cost more (unless you consider the Flight Control), and the SMT
irons and wedges generate more spin (milled faces).
Wishon is another outstanding choice, of course, but tend to be a touch pricier.
As for the $10 assembly; you're getting the Asian assembly job. In other words, you're getting the same assembly job that they do in Asia for the OEMs: Trim to lengths, glue and stick. Granted, in the GW $10 deal, they say they'll build to your specs... so in theory you could get a helluva deal by asking for all sorts of great specs that would force a decent job - like calling for a specific freq slope built around a 5 iron target, and specific loft and lie requirements. Fantastic deal if they'll do it for only $10.
Better built by a PCS'er? I would certainly hope so. More expensive? Most likely.
Your fitter should make a shaft decision for you, based on swing speed and your height. But at 6'5", I think you should be finding your closest registered True Length Technology fitter, and having them build the set.