I'm not going to say what is best for your situation but what I can say is this.
I run a mild L28 with 40mm webers.
With 36mm chokes it was dyno'd at 216hp at the wheels, on the same day with 32mm chokes it was dyno'd at 210hp
When changing from 36 down to 32 chokes I gained 10hp at 3500 rpm, where my motor runs most of the time.
40mm webers are cheaper and more plentiful than their larger siblings, often round the $1.2k mark.
For me, if you are running a street car that dabbles in track work and is built at a budget, 40's all the way.
If you're building a hi-po L series, where 50's are justified, sounds like a very exxy build, I would be looking at injection personally.