Where is a good place to get a longer handle for a Muhle R89?
My Muhle R89 is a great razor but the handle is definitely too short for me as I have huge hands
Connaught shaving is a good place to look (always worth checking their clearance/seconds stock too).
eBay can be good if you search "stainless steel razor handle". I can recommend the "Windrose" handles, I bought one of their heavy handles a few years ago and it transformed my 1940's Gillette Service Set Tech (my ever-day razor).