I think I'm getting a handle on this infrared stuff. I've found metering it at 3 asa (thats as low as the Minolta VF meter will go) then opening one more stop, I'm getting consistant results. I do enjoy that I don't know exactly what the shot will look like when I shoot it.
on the techy side, I'm surprised your shooting it that slow with a yellow filter. I've only used it in 120 format with an orange filter and a homemade E6 (unexposed, developed) filter. With the orange filter I'd expose at about 32asa (need to double check notes but pretty sure) and the E6 'special' needs 5-6 stops. With the orange filter I get a similar look to what you've got here. With the E6 it goes wild, more HIE like. I have deleted two examples I had online of this otherwise I'd post a link. If you want a look yell out.
I haven't used Maco but Konica, which is supposed to be rated at 32 with a red filter, i shoot at 100 iso and pushed developing up one minute. Just means i don't have to lug a tripod around everywhere.
I bought a red 29 filter at the same time as the yellow I've been using, but I haven't tried the red one yet. It is rated at the same 4 1/4 stop correction, so my metering should be the same. I'll try a comparison test in the next week or so.