Your most likely already well aware of the issue of the larger rotor heads spawing on the smaller bases, but I though i'd report it anyways encase there are any updates you've made recently in fixing it.

Yes i am well aware of that situation but there is no known workaround, hence why i added it to the mods description:
"Right now the rotor has to spawn with a large rotor head (rotor) because there are two issues with how the game handles rotors. Though that will be fixed as soon as possible (the engine lets me to do that)."

I did however request a feature to circumvent this in the mod request thread.

Though thanks for posting it here too, so anyone else will spot it as current "bug" as we cant do more than this, yet.
So lets see what happens ... :)

The world example of this loads just fine and the minirotors provided work just fine, but when I try to cut and paste a small rotor head onto a minirotor I have placed and removed the head from, it will not paste. The head just floats right through the lower rotor part. I just can't get it to 'snap' into place. Also the vanilla version does not work for me either, (putting a small block rotor top onto a large block rotor lower part. Is this just me or is the whole thing wonky?

Yes there was a change a few months ago that requires rotors to call the "attach" action in order to snap.

For it to work you can use this script:
http://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=392089767

Just place a single timer block and a single programmable block, load the script ot the PB, setup the timer to run the PB and then "trigger now" itself.
THen start the timer and it will continuously run the PB.

That way you get the old functionality back.

Hey. I found a bag and would like it to be fixed. Your rotor's torque is always marked as unsafe value if its even 0.01% above 0