No such thing as VFR On Top !
VFR rules above 3k feet and below FL100...
... in Class B, C, D, E, F & G airspace...
Cloud clearance 1000 feet vertically, 1500 m horizontally, min viz 5K.
Nothing different for micros.
He was certainly that in all the shots I saw (and I've now watched it twice). In all the shots, you can see ground, so he was not above solid overcast.
No-one in that programme entered and flew in cloud.
I'm really missing our old Thruster TST, which we sold in October. Wish we'd held on to it and rebuilt it now.