I may try mounting a separate fan, that is a good idea.
I have the min layer time set to 20 seconds, but some layers still take less than 5 seconds, due to the minimum print speed.
As for the z height, the code is inserted between the Z moves that account for settle. So by default, the end of a layer is when the Z drops, then the wait code (or any other code per layer) is inserted, then the Z raises to the correct height for the next layer. This luckily means the print head is about 0.25mm from the top of the build, which appears to be enough space to not melt everything.
I received my creatr in late December, so I believe I have the latest hardware revision. It comes with more or less stock marlin firmware, I can look up the version on Monday. Overall I really like the printer, but it is my first 3d printer, so hard to compare. Getting the bed level can be tricky, and while having a huge print surface is awesome, it makes it more difficult to level the bed, apply kapton tape without bubbles, etc. This fact is one thing that draws me to kisslicer, as I can have it create a raft that eliminates these issues.
As for Leapfrog's filament material, it is made in China knock-off junk. The spools are only labeled in Chinese and the print quality has been mixed. When they spool fine, everything is fine, but often the filament is tangled or twisted under itself, killing the build. I've also had some spools where it looks like the plastic filament was so hot when spooling it stuck to previous layers, again killing the build. I also have not had much luck getting ABS to stick to kapton tape, even with 60-80C bed temp. It will stick ok to blue painters tape or aluminum tape, but only with ABS plastic dissolved in acetone and spread over the tape. With some PLA I sourced from amazon, I've had good luck printing directly on the heated glass.
Speaking of the heated build plate, I'm pretty sure it can only get to 85C or so. I have not measured it other than the built-in thermister, but that is where it platoes and cannot climb higher. The build plate itself appears to be plexiglass, not actual glass, and is rather thin. This has caused it to bow up a bit overtime. The Z end stop is a proxy switch, which is nice but I cannot figure out how to easily and reliably adjust it, I'm stuck with changing the Z offset before each print (G1 Z0.6; G92 Z0).
Mostly minor gripes, but that has been my experience.
The flow tweak of 0.5 means kisslicer's default extruder settings would cause about 2x more material to come out than is actually required. A flow tweak of 1.0 is stock, but the prints with that would cause so much material to extrude out that it would "dish" and form a wall. This causes the print head to hit the wall and skips the x/y stepper motors, moving the print. This looks like this:
http://www.thingiverse.com/derivative:55874 By lowering the flow tweak, I've been able to get better prints out of kisslicer.