Whole point of custom fit is exactly that, fit clubs to you and your swing. So length and swing weight should be sorted during fitting for club builder to ship to specs. I have always trusted the process and not done me wrong yet 🤞
Hi Jaws... First, thank you for replacing me as the tallest member of this forum. I'm 6'7" and hoping to shrink in my old age so I can shop at regular stores.
Allied to, but not necessarily an on point answer to your question, let me show you something I've done for years, but first, a moment to digress. Maybe it's worth knowing about or trying.
Without going into detail about the fitting that proved I have short upper arms that make my wrists a lot higher off the floor, I've had fittings over the past 40 years that suggested between 1" up to 2" extra long clubs. (With the subsequent lie adjustments too)
At 72 years old, I don't generally buy new clubs anymore. Quite honestly, with what's left of my game, the newest irons and some older irons don't perform much differently for me and feel is pretty much my most important criteria for what I use.
Since I've learned how to modify my clubs myself. I get a standard set of irons with the 5 iron being 38" up to 38.5" and add extensions so my 5 iron is 40" long.
Nobody makes a backweight that is made to go in an extension, so I had to invent it. Pic below...
Basically, it's the extension and a 40 gram teardrop shaped fishing weight. Put the weight inside the extension upside down. I usually put some wadded up duct tape on top so the weight won't rattle around. Sometimes I wrap tape around the weight to make the surface contact better. The 40 gram weight more than offsets the 12 points of extra swingweight in a 2" extension and my irons swing between C3 up to C5, depending which set I use.
I've epoxied the extension in the shaft, as suggested, but other times, I've wrapped a piece of duct tape around the part that goes inside the shaft. As I hammer it in, the cloth peels off the tape and leaves the glue between the extension and the shaft.
BTW - The extensions are available in specific diameters, so it's a good idea to strip off one grip first, use a micrometer to measure the inner diameter of the shaft, then buy the extensions to fit perfectly.
Yeah, it's goofy, but it works for giants like us.