Lavi had a ITR higher with less TWR, carrying a higher fuel fraction than F-16, to put it simple a Lavi was capable to out turn an F-16 even having less thrust.
read this link
http://john-golan.blogspot.com/2016/05/lavi-engineers-perspective.html
research means the Israelites studied not only...
Lavi had not a single aircraft configuration but several, in order to choose one they had to test different aerodynamic variants just for a canard or wing besides the structure uses several new innovative solutions that implies thousands of research hours, this transform into data, that data can...
pictorial evidence is also guess you are seeing what the puppet masters let you see, there are also satellites and pictures where more than 20- 30 aircraft should be seen, if satellites can not see 20- 30 aircraft, then the number is low, no pictures of 5 or 6 J-20 together the number is likely...