Kriega bags are "reassuringly expensive"... very well made and the 20L bag will also become a holdall or a backpack. But I mainly bought them for the ability to get them quickly on and off the bike if commuting. I can see how your solution works well for a bit of touring. I'm currently trying to decide between the Motech Blaze saddle bags and the Kriega US 20L + US 10L. As you say, the Kriega are easy to get on and off the bike, and the 20+10L would also provide three different options in terms of volume (10, 20 and 30L). Expensive, but tempting nonetheless. I've got the Kreiga bags (one 20ltr and two 10 ltrs) to supplement the top box on my Tiger. I highly recommend them but as [mention]raesewell[/mention] says they are not as secure as hard boxes, but are much more versatile.