I had the yellow filter on because I was using HP5+ (I would have prefered FP4+ but didn't have any) so I put the yellow filter on as I knew I would be mainly taking outdoor shots and the one stop reduction would be useful as the Voigtlander's top speed is 1/300. And any increase in cloud to blue sky contrast would be nice too.
I should have taken it off so I could have used 1/125 instead of 1/60 although it all seems o.k.
At events like these I don't meter internal shots. I meter outside and set the camera then if I need to take an interior shot like this I usually just slow the shutter speed down to something I am happy with then guess how much to open up the aperture.
It usually works so I am either very good or very lucky at guessing exposure (I suspect the latter).
Your system works well, Steve. I had forgotten about separate metering. As an "automaton" whose camera meter gives a reading every time I press the shutter half way down I tend to forget about these things and hadn't for the same reason given any thought to using a filter as a shutter speed aid. Having said that I now remember having D3200 in the camera once and putting every filter I possessed on the lens in a vain attempt to create blur in the cylinder operated by the Isle of Mann Laxey Wheel.