With the FAS Modern, I set it up depending on the sound I'm going for. If I'm after a focused tight sound I set the the MV under 5 and adjust the low cut in the advanced page to suit the sound and guitar/pickups I'm going to use.
If I'm after a looser more open type of tone, I up the MV to 7 or 8, and again, set the low cut in the advanced page of the Amp block. I do the same with the Cab block low cut. Adjust to taste and gear. For very specific tones, I
will use the Amp GEQ, mostly to cut. Remember the low cut in the Amp block is before the preamp and power amp sections. The high cut is not on the input side. This at the end of the preamp section if I remember correctly.
Wiki search. 
So, if you usually would use a boost pedal before the amp, you can get a very similar result with the low cut and input trim/boost/more gain. This works on all amps and IMHO is super helpful for getting that tone you hear in your mind.
Me, I like to boost with a pedal, or a filter, or a PEQ...but not always.
...where in the chain do you use it? Is it something that could still be effective in post (like in the DAW) or does it need to be used while recording?
...would you mind pointing in the right direction on some basic settings to add that squish undeunder 100k?
Since I NEVER have luck with any of the Mesa amps (especially the Dual Rec, & that's what most of those guys used) i'm gonna give the FAS Modern a spin... what settings you guys like? What do they work well for?
The MBC is typically used at the end of the chain, but there are no rules. It can be used pre or post recording.. Depends on how you like your workflow to....flow.
From default settings, and REALLY depending on what you're using, like a bass or a guitar. BIG difference. Set the low frequency to your liking. On CH2 and CH3 set the ratio to 1. Then palm mute and adjust the thresh, ratio,
attack, and release to your liking on CH1. I like a fast attack and semi fast release. Best to use your ears, and do it at gig volume if you plan to use this live and make sure you are not killing needed frequencies in the mix.
About the Rectos, see my above suggestions for the FAS Modern. Same things apply. Because guitars, pickups, technique, hand tone, rig, ect ect, its hard to find patches from others that will work for you, but knowing how
your tools work is key to going from tone chasing to, tone nirvana. The
WIKI is super helpful and has tons of useful information and answers to questions that we all come to.
Hope that helps someone. :lol
These are just my opinions, if you blow your shit up because you didn't do any testing before you turned it all the way up, that would be user error. :twisted
