A home tournament that overruns does so for one reason: the blinds did not keep up with the chips on the table. The finish time is set by the structure, not by how people play.
Give it the field, the starting stack and how long you want it to last. It produces levels that rise at the right rate and land on values your chips can actually make.
A tournament ends when the average stack is worth about ten big blinds, because at that depth every pot is all-in and eliminations come fast. Working backwards from that is how the last level gets chosen, and everything else is a smooth climb towards it.
Twenty-minute levels with a steep climb and forty-minute levels with a gentle one can finish at the same hour and play nothing alike. Longer levels reward patience; shorter ones reward aggression and finish more predictably.
Introducing an ante roughly doubles what is in the middle before anybody acts, which is what forces play to open up. Bringing it in about a third of the way through is the usual compromise.
Three to four hours suits most kitchen-table games. Under two and it is a coin flip; over five and people start leaving.
Something that divides cleanly by your smallest chip and gives 100 big blinds at the first level. 10,000 with 25/50 blinds is the usual default.
Around a third of the way through the levels, which is what this generator does.