I am no expert and am offering a possibility not an definitive answer only because none seems to have been offered.
Would using TE energy cells - which allow output limitation - used as buffers provide a solution?
That's actually what I ended up doing... but not because it solves the problem. It doesn't. If I manually throttle the dynamos through another block, then they cannot throttle up on demand.
What it does instead is completely circumvent the problem of having multiple dynamos in the first place. I dismounted 3 of my 4 dynamos and threw them back into storage, and placed a giant buffer cell instead. Now my base is powered only by a single dynamo, and short spikes of power are buffered by the cell, which gets recharged in between periods of activity.
It's not an ideal solution because it might potentially stop working properly once my passive energy drain gets closer to the dynamo's maximum output rating, but since multiple engines apparently cannot throttle intelligently, it's the best I can get right now.
I'd love that feature to be added, by the way - I'd even take it as an optional upgrade that I need to spend a slot for. Something like a "Engine Bank Network Adapter" that lets those engines which have it installed and are connected to the same fluxduct line talk with each other and coordinate their throttle. ...Does Team CoFH accept suggestions somewhere?