Johannes Andersen table / Harry Ostergaard chairs - how to proceed?  

Thanks leif...
...I took the chair bottoms to the upholsterer today and asked if they can duplicate the look of the seam on the bottom. The fellow took a look at the band and said something like "Oh, that strip is the underside of the vinyl, yes, we can do that," which was nice to hear. He did not, however, write the request down on the work order, so I think I'll call today to ask that that be done so it gets conveyed to the upholsterer.
The chair frames - I took the two that were too short (from the legs being shortened), along with a standard height chair to a local refinisher. He had some chair legs in the shop that, when stained, looked convincingly like my chair legs. He also gave me a quote to strip the chairs and reglue any loose joints. Now, all seven chairs are there waiting to be stripped and glued.
That's the update on the chairs.
Gary

I'd be interested to see how...
I'd be interested to see how the chair leg replacement turns out. While the general shape of the turned piece is probably very similar to many other chairs, I think it will be very difficult to do an exact match to this design.
Both rear legs have a distinct inward taper to them, followed by a smooth transition to the double (maybe triple?) curved backrest. That hairline dowel joint will be a challenge to replicate with a leg not made for that geometry.
Finally, the chances of getting an exact match for the seat rail geometry fit and dowel connection seam slim as well. Any loose fit here would be visible and affect joint stability.
Apologies for the unsolicited advice, but I'd be more inclined to leave the framing of the two shorter chairs as is right now, but continue with reupholstering all seven seats. Eventually, you should be able to find three more chairs (sets of two or singles?). Then you can move the seats you've already upholstered to the new chairs and sell the two shorter ones with the other seats as a pair, leaving you with a nice set of 8 without any Franken-chair pieces.

Hi cdsilva
It sounds like I wasn't clear in describing the work that will be done to raise the chairs to their original height It is not our intention to attempt to duplicate entire chair legs.
The intention is to take eight existing chair legs from a surplus supply in the shop to be used as donor pieces. Then using one of the original height chairs, measuring how much will need to be added to the bottom of each chair leg - my guess is ~ 1 inch. If this estimate is correct, 1 inch will be cut off the bottom of each donor chair leg. A center hole will be drilled into the bottom of each Ostergaard chair legs. Coinciding holes will be drilled into the top center of each 1 inch extension piece. A dowel will be used (along with glue) to join the original chair leg to the extensions. The 1 inch pieces on each of the eight legs will be sanded so the joint is smooth and the taper appropriate. Then the extensions will be stained in an attempt to match the existing color. At least, that's my understanding of the process.
However, I can certainly see the merit in your idea of upholstering the chair bottoms and waiting for a nice, original single or pair to show up.
Gary

Sorry, Gary, I didn't see this
until now, but Leif's advice is sound. I would also maybe ask the upholsterer to show you the work on the first chair before he proceeds to the rest, if you're not 100% confident that they know what you want. I think if you ask nicely and explain that the method of upholstery is important to preserving the value of these vintage chairs, they will understand and be willing to oblige. I hope. If it were me doing the work, I would be happy to email a few photos.

Gary, your explanation makes...
Gary, your explanation makes a lot more sense than my assumption. Sounds like a pretty good plan if the diameter is exact and the wood grain/color are a close match. Please post photos when finished.

Sorry for a bit of a tangent here, but can someone recommend a good tape product/brand to use on the underside of reupholstered dining chairs? The tape should be good for 1) sticking to wool/vinyl/leather, 2) sticking to wood, and 3) strong/tacky enough to flatten/hold any wrinkles in the upholstery, so that it's not visible when in use.
The electrical tapes I've tries so far seem to start peeling off after a short period of time.
I was thinking 1" black cloth gaffer tape is the way to go, but there appears to be many types out there of varying quality.
Thanks.

I have a roll of gaffer tape (black fabric, 1" wide) made by Pro-Gaff that is identical to the stuff I've seen underneath Møller chairs, or at least identical as far as I can tell. Comes in a variety of width and colors. Sticks well. Stretches around curves. I've noticed that Møller also affixed their tape from the factory with a few staples, maybe every 3" - 4" with narrow staples (maybe at 1/4" crown or so).