Both should work, unless you write something like
var count = 999999;
memcpy(..., 4*count); // or sizeof(var) instead of 4
Then, at least I think so, would the calculation be treated as a var result (because of var times integer) and therefore be limited by the var range (or get negative to be more precise, or positive again but at a number way too low).


Don't write random waits into your code, that does more harm than any good. Everything you write gets executed instantly and in order, and the program only continues after the current instruction or calculation has been finished (in a single threaded program like the default acknex engine).
There are (and/ or were) only a few exceptions for which there were reasons or explanations, of course. For example level_load in old acknex versions (like A5, where it was executed not immediately but at the end of the frame => wait(1)), automatic bounding box initialization at the end of the frame for entities created by ent_create (therefore a wait(1) before c_setminmax() on animated models), DirectX initialization at the end of the frame or functions using wait themselves.

In general: Don't use wait unless you really have to, like for default entity loops.