Let's go through and find timings the right way. I'm probably going to focus on drawing first, especially in conjunction with what techniques are actually used in games. I'm hoping we can settle once and for all what the actual limits of Ti-Basic are.
Let's start at the beginning.
startTmr→A For(B,1,100000 End checkTmr(A)→B Disp B
I get 122 seconds for this running on a Ti-84+SE, 136 if you close the parenthesis on the For loop. So that's 1.22 milliseconds the For loop adds to whatever command we're testing.
startTmr→A For(B,1,1000 Disp " End checkTmr(A)→B Disp B
I have 52 seconds for this, which puts a blank Disp at 52/1000 - .001 = 51 milliseconds. I measured additional character in the string literal as adding 1ms, including the closing quote. So it can be summed up nicely as Disp takes 50 ms, plus 1 millisecond for each char in the string literal, including quotes