Thanks for all the replies
I use the Shimano SPD-SL system and run regular Shimano 105 cranks and pedals on all my bikes.
My shoes are size EUR46.
I have tried to use washers and then 16mm extenders (tested for over 200km so far) and find it pretty nice and no issues for endurance ride but not for fast rides where I need to put down power (my body needs to get use to the wider stance).
The extenders did help with solving the issue where my thighs rubs frequently against the top tube and tip of the saddle when I ride (I have big thighs).
Anyways, turns out I have one new pair of shoes I haven't use (totally forgot about it) so I re-unboxed it and tried it and surprisingly it does not rub the cranks.
Shoes 1 (No rub) = "Tiebao" brand with 3 Velcro straps. This is already worn out / old.
Shoes 2 (little rub on cranks) = "Speed" brand, white color with 1 lock knob and 1 Velcro strap.
Shoes 3 (major rub on cranks) = "Speed" brand, white color with 2 lock knobs.
Shoes 4 (No rub) = "Speed" brand, gold color with 2 lock knobs.
One major note here is that no matter the position of the cleats (I tried several positions just to experiment), the shoes that rub the cranks would always rub the cranks.
In summary, I find that most shoes in same size may not have similar width hence may rub the cranks especially for big feet riders.
At the moment I've removed the extenders and just use shoes No.4.
Would be nice to know the shoe brand of anyone here that use size EUR46 or larger shoe size that does not rub their cranks?
Thanks!