I actually went back after I took that picture and slid a little heatshrink over the resistor/wire to insulate it better. I'd highly recommend doing this if you go that route as it will prevent any accidental shorts against the inside heatsink. Also, just for reference the resistors I used were mostly 39 Ohms. I may have had a couple 45Ohm in the mix, but it lowers the fan speed enough that it still blows a good amount of air but isn't as annoyingly loud as the straight 12v.
Heatshrink is a good idea to insulate that hazard waiting to happen, I had thought of placing a heatshrink on the axial resistor (VMOD3) but decided against for now.
As for the fan ripping away, I have stowed them miners away in a ventilated cabinet which takes away some of the noise. Power wise there's not a lot saving from the slower fan, so since the noise factor is reduced, I don't mind them running full speed for now. I was planning to put a 39ohm too after seeing yours but a 1/2w with the heatshrink, but I guess I will let the fan blow full speed until I figure a heatsink for the MOSFET's. I dug out some TO-220 sleek heatsinks, will see if it will work, or will order some like chanbergs (saw some on Amazon sold by cosmos in a bag of 20s).
BTW, did you use adhesive thermal paste or thermal pad to stick the modded heatsinks over the MOSFETs?
I actually just used a very small dab of Arctive Ceramique and let it set. Once it's been run through a cycle of hot/cold it seems to hold very good. I have the same Ceramique that has been holding a heatsink on the cpu of a lan card for years, the lan card stands vertical and even without glue the Ceramique holds the heatsink on it.