Hi there, has anyone got experience with the Harvia WHP1500 chimney set? We are buying the Löyly IKI Wood Burning Sauna Heater for a commercial mobile sauna set up, and were advised by one supplier to go with the IKI T600 chimney pipe packages, whereas another supplier suggests the much cheaper Harvia WHP1500 chimney set (HUUM and IKI compatible). We have done quite a bit of research but can’t find any conclusive advice online. The IKI T600 works out £1,573 more expensive! Any advice would be much appreciated! 
@HeatConstruction is this something you have experience of?