A JavaScript function to calculate the best delay between a certain amount of tasks to evenly distribute them within a time range.

bestdelay.js

// organize tasks at equal intervals within a time range.
// receives two objects (start and end hours) and an integer (tasks)
function spreadTasks(start = {h: 0, m: 0}, end = {h: 23, m: 59}, tasks) {
    let totalHour = end.h - start.h;
    let totalMinute = end.m - start.m;
    let totalTime = (totalHour*60)+totalMinute;
    let taskTable = [];
    for (let i = 0; i <= totalTime; i+=(totalTime/tasks)) {
        let taskTime = ((start.h*60)+start.m)+i;
        let taskHour = Math.floor(taskTime/60);
        let taskMinute = Math.ceil(((taskTime/60)-taskHour)*60);
        let taskSecond = Math.floor((taskMinute-(((taskTime/60)-taskHour)*60))*60);
        taskTable.push({
            "h": taskHour,
            "m": taskMinute,
            "s": taskSecond
        });  
    };

    return {
        "delay": {
            "m": Math.floor(totalTime/tasks),
            "s": Math.floor((Math.ceil(totalTime/tasks)-(totalTime/tasks))*60)
        },
        "schedule": taskTable
    };    
}

spreadTasks({h: 7, m: 20}, {h: 12, m: 30}, 15);