The Matador ones are 1/76 and don't quite fit the Emhar 1/72 tanks. They are the only ones I have direct experience of, however, I would recommend not using them. Instead I would try either the Mister X or the Modelltrans ones, because both of these were made for 1/72 tanks. Actually, thinking about it, maybe the Modelltrans ones are made for both Airfix 1/76 and Emhar 1/72, so I'd go for the Mister X ones which are definitely 1/72.
The Matador ones are 1/76 and don't quite fit the Emhar 1/72 tanks. They are the only ones I have direct experience of, however, I would recommend not using them. Instead I would try either the Mister X or the Modelltrans ones, because both of these were made for 1/72 tanks. Actually, thinking about it, maybe the Modelltrans ones are made for both Airfix 1/76 and Emhar 1/72, so I'd go for the Mister X ones which are definitely 1/72.
I would also go for the Mister X products but can you get them in the UK? Certainly I would like to get my hands on the supply conversion. Contacted Hannants about those new FT17 (sic) but their buyers appear not interested in them.
For Mister X models you should send a PM to "crashandbern". He seems to have a way of contacting Mister X, a bit like Peter Parker can contact Spider-Man.
For Modelltrans, I believe they are contactable through their blog, although I buy their products through Tracks and Troops (service is a bit temperamental).