Hi, here is the preset. It is not supposed to sound "good" as is, but it is my starting point to dial in a bass tone. To give you some context : I use the FM3 in the studio, never live. I always dial in the bass tone after drums and guitars. So it is supposed to fit in relatively "filled" context.
The tone is essentially dialed by tweaking the drive blocks.
You get three rows (ultra hi, mids and low end) :
1 top row is the very high end with a clean DI with a filter to only let the fret noise through, it is mixed after the cab block. Less is more with this one. It's out of phase with the rest but that high it doesn't harm much. It helps cut through cymbals and guitar hi end.
2 middle row is mids : that's the heavily distorted part. It is filtered and goes into the cab
3 low end : here the drive block doesn't do much, but it is important to have it in because the drive block adds latency and shifts phase. Having a drive in each row makes them easier to mix without phase issues.
That is basically it, I don't know if it helps, but here you go