I would suggest this saddle bag for long distance group rides

Also if you regularly cycle in poor weather condition it would be ideal as the waterproofing is top notch and you can easily store personal possesions such as phones

For the size of it its remarkably light compared to my compact saddle bag

Fast delivery easy to put on the saddle robust plenty of room for its multi tool tyre levers and inner tubegood product best value saddle bag i have bought so far