Clarification about Builtin Arrays

My game has ground to a halt when I heavily use arrays in Unity. So I tried to create builtin arrays, to see would that speed things up again. ? Can I do this:

I’m just not sure if I’m obliged to type values into the inspector, and if I’ve changed a builtin array to a JS array class member. Thanks.

Thanks, but it must be OK. It has made a huge different to the speed and things seem back to normal now. Great.