Yeah I also prefer that way, its much better, so yeah go with that if you want to change files dynamically. And the table you see in the help patch also has a build in "bleeep" silencer. Without that build in, you will hear an anoyying BLEEEEEP every time you change sound. With this specific table version you get silence instead of bleeep.
No there wil be no change when utning on/off the envelope. The envelope uses very very little, DSP, so dont worry too much about that.
Here is a list of what the different tablesize are equivalent to:
8192 = 0,17066666666667 seconds
16384 = 0,34133333333333 seconds
32768 = 0,68266666666667 seconds
65536 = 1,36533333333333 seconds
131072 = 2,73066666666667 seconds
262144 = 5,46133333333333 seconds
524288 = 10,92266666666667 seconds
1048576 = 21,84533333333333 seconds
2097152 = 43,57816666666667 seconds
4194304 = 87,38133333333333 seconds
Since you want to load many samples, you should probably only assign the table size needed for each sample. And you need to use a different table for each sample . Dont use bigger tables than you need in general, since you have kind of limited resources.