It works out well enough, with my Trekking bike I wrap the AXA ring lock's chain around my seatpost ,

and over the 2 arms sticking backwards, they bend down and are spaced the same
as the holes in the bag that the usual straps go thru,
then I tie my mini pump onto the bracing dowel inside the bag.

sets the bag back further than strapping it to saddle loops would. a good thing..

The Randonneur set like good sized front handlebar bags with a small rack beneath them and fittings to the handlebar
that keep the bags as low on the front as practical, certainly no higher than the bars themselves, and plenty of room to grip anywhere on the bar top.