Thank you!! I definitely want to do a FET47/MD421 pairing on the bass cab, and I am quite intrigued with the U87 in Figure-8, I'll have to give that a go as weel.
the figure 8 neumann is a beatles technique, its thin without DI for modern styles (though I like it for busy parts), you'll have to compensate for the delay, but you always do with a DI... if you use protools or cubase you can setup your amp/cab/microphone as an insert effect off a mult of the DI track and use the delay compensation by pinging the amp, it'll get it in time in those 2 DAWs, the you print another track off the output of the track with the amp as an insert... hope that makes sense.... or you can do a reamp if you don't need the feel of your amp to give a good performance... anyway, lots of figure 8 mics work in that meter-out position, the U47 or 67 were the beatles choices, but a c414 or AT4050, even a lowly warm wa47jr can work. I've also used ribbons for this. Shure's (formerly naked eye) is pretty good at it as is a royer 121 or 10... an AEA works but is a really warm midrangey sound, depends what you're trying to emphasize in the mix and the preamps available.
I'm also in the process of building a Sub-Kick, have you paired one of those with a FET47?
I usualy do one or the other, not both, on kick... if I use both its because I can't comit to one or the other, but I usually just decide on soemthing, soemtimes arbitrarily, often based on the rest of the arrangement, at leastn on luxurious sessions, those don't come up as often these days.
I don't like recording a bass cab with a subkick. A reversed woofer on what's essentially a woofer seemed like a cool idea to me but in practice it was all the wrong frequencies, you have to EQ it so much its not worth it. If you have a subkick on your kick its definitely a bad idea unless you like an undefined bottom end.
EDIT:
Another point in favor of the 47fet is the headroom, I like loud amps even in the studio so I need to be able to soak up SPL...and isn't the m149 transformerless? the 49 is the OG, I could swear the 149 has no transformer so you can hypothetically capture below 20hz, but do you really need that? the fet47 doesn't extend all the way down but the transformer gives a nice bump before the rolloff. it would depend on the song and the bass' roll in it and what's going on with the kick
Thanks for asking, I never get to talk about this stuff on here. Cheers.