The only thing I would say about the Tortec is it is quite a narrow rack, and the velcro strapped on type rack bags can tend to flop around from side to side on it a bit. They don't actually fall off though and it is a very very light rack. ...
The narrow Tortec racks, and similar, aren't really meant for top bags, but for carrying panniers.
I don't consider the Tortec Ultralite as narrow at all. My Creek2Peak rackpack fits on it perfectly well and it's not a thin rack pack.
The Tubus Fly, however, is much thinner and rubbish for rack packs (but fine for panniers obviously).
Anyway, back on topic...
After a few recent incidents I'm going to stop recommending the B&M D'Toplight. My complaints with them are:
* The single screw that holds it all together falls out too easily. On a recent commute I hit a bump in the road and the whole thing committed suicide into the road (recovered but the screw is lost). Poor design.
* I've had 2 with dodgy switches meaning I have to find the magic position somewhere between on and off for it to work (luckily it stayed in this position once on). More poor design.
It's a shame because I like the rest of the design (the size/shape and the built in reflector) and it's not stupidly bright so it won't dazzle people in 2 tonnes of metal coming up behind me at speed.
Time to get a Cateye carrier mount and use some of my old Cateyes (TL-LD1100) although it does leave me without a rear reflector.