I reckon you'll be right. I wouldn't take off the heatsinks though. Leave the sinks on, take the fans off and maximise the surface area - even leave the fans on and circulating around the sinks. I'm pretty sure that was done in a couple of the older projects I've seen on YouTube etc. You'll need an absolute butt-ton of flow directly at the die to counteract the surface area provided by the heatsink, and I'm not sure that'll work out so well. The outlets pointing at the GPUs is a good idea, just point them at and around the sink fins and you should be right. I know you're not fussed about killing the gear, but I think you'll fare a lot better keeping the sinks on at least You've also gotta keep an eye on the oil wicking up the cables back into the PSU, onto the floor etc. You can get around this by using extension cables to plug everything into the PSU above the oil level I think.