Spoon bits are a subject I hope to add in the future. Keep watching.

Four years too late; I hope you found one. If not, a 1:8 and 1:7 is a commonly available reamer as it is the same taper as many light truck and jeep tie rod ends. You can even find them on amazoni with a 1/2” shank. You merely have to assure that your spindle master patterns and leg patterns are representative of the taper of whatever reamer you acquire. Veritas from Lee Valley is 6.4*, others are 6*, 9*, with one chair bit stating, “12 degree included angle” which in chair-speak is 6* Hopefully I got that all right as I went from memory and it’s late do I’m sitting here doubting myself. Either way, you can make your own reamer or several at whatever angle you wish. Turn a 5-3/4” taper with a 10” long straight spindle on the handle end from ash or white oak. Saw down the center of the taper with a fine coping saw or thin dozuki. Cut and grind the same taper from a six inch steel scraper or even a wide sawzall blade and true it. Burnish the four o’clock and two o’clock edges like a scraper, turning a burr over. Instant homemade taper reamer for wood.