My partner's coal-only policy is stalling our custom knife commissions

I've been collaborating with another smith on high-end custom knives, and he refuses to use anything but a coal forge for the entire process. I get the authenticity, but our turnaround times are suffering, and clients are getting impatient. I've suggested integrating a gas forge for initial heats to speed things up, but he says it compromises the 'soul' of the blade. We're butting heads constantly, and it's starting to affect the quality of our work. Has anyone dealt with a similar stubbornness about traditional methods in a partnership? How did you find a middle ground without ruining the dynamic? I'm worried if we don't adapt, we'll lose repeat business. Looking for any advice on balancing craft integrity with practical efficiency.