threeapples- Just like many other aspects of your build that you have encountered, I think the carpenter is unfamiliar with this manufacturer as well as the install method. It sounds like he is comfortable with the standard wooden baluster method and so he is pointing you in that direction and trying to ensure you go his way by suggesting that the one you've already specced is unstable. And no one wants an unstable railing on their staircase, right?

I have no hands on experience with installing balusters, balustrades, etc. However, this company has been making these since the mid-40's. I think that says something about their stability. A quote I pulled from the King website: "Internationally acclaimed, GRANDE FORGE can be located in the finest hotels, restaurants and exclusive residences in all five continents. " If their product is stable enough to be used in hotels & restaurants with all the abuse that goes along with these type of businesses, I would surely think it would be stable enough for a single family home. And how many upscale hotel, upscale restaurant, and exclusive residence installs has your carpenter done that included this level of balustrade/baluster work? That may tell you all you need to know.

Perhaps someone from King Metals or Grande Forge could talk with the carpenter via phone about his concerns on install. If he's worth his salt, your carpenter should be ok with talking to them to learn how to install this system properly so that there isn't any wobble. If he's not willing to take the time and energy to learn from the supplier/manufacturer, then maybe its time to find someone who is familiar with this product to install it. King or G-F may be able to help with a referral for an experienced installer.

Hope this helps!

Out of curiosity, who is playing a larger role in the specs for the house (direct to the GC/subs)--you or your DH? As a female who specced most everything (DH & I were on the same page with most everything, he just preferred to not have to deal with any of it if someone else was willing to take on the job), I can tell you that many GCs and subs don't want your female input. They want to do it their way and don't trust your way unless it matches theirs. However, if DH steps in, a very small amount of push back ensues in the form of GC/sub making their suggestion, DH says, "No, I want it this way" and it magically gets done with no more push back. Just a thought if you haven't already tried this tack.

I voiced my opinion on this before, but I still have to agree with mydreamhome again. If this was a wobbly product they wouldn't be successfully selling it.

mydreamhome, very good points. my carpenter is nervous about the welding aspect of connecting the handrail to the balusters. my builder said this guy has welded before, but he seems unsure about it. i sent the link to my builder on friday, so we'll see what happens when he looks at it.

i've been working on the staircases on my own (with dh's input) and my dh has his own projects within the house.

i'm meeting with everyone again in a few days and will see what happens. i think, more than anything, my preferences and tastes are just not in-line with what the norm is around here.