Is there anyone with real hands on experience on this topic?

Kyosho show minimal cut-outs for their .46 sized ARF cowls - carb inlet, glow and external muffler, that's it. OS has confirmed this is OK, yet hobby shops and everyone at the field will tell you to cut your cowl to pieces to allow cooling. Is this just overdoing it though?

Does anyone out there really know the truth, checked engine temps. etc.?

I have just finished a P-51D Mustang and am anxious to know. Failing any info to the contrary, I will follow Kyosho's instructions and see what happens. After all, it is only a small engine. For larger engines sure, I would go with a bigger cut-out because they give off more heat.