thats why in an earlier post i said that you must consider an angle tolerance of plus or minus 3degrees when tuning VTC

i think 40deg would be max for a stock engine, like you said, 45-50 really wouldnt help much
hence the Toda 40deg being a great bolt on product (not that its hard to modify a stock one if theres a reliable machinist nearby)

and again - i am still trying to find somebody that has clayed a motor running high VTC to see what kind of clearances there actually are
there are stories of VTC slipping past their allowed tolerance at both low constant RPM (cruising) and high raising RPM (acceleration)
in most cases the bottom end is destroyed along with valves - even if one cylinder goes first the intake manifold will be filled with peices of piston and valve which get sucked back into the other cylinders