Topeak Explorer Tubular Rack two versions confusion There are two versions of the "Topeak Explorer Tubular Frame Mounted Bicycle Rack"

'regular' (TA2026-B) and 29er (TA2042-B )

I'm not sure what would work best with my 700c hybrid bike?

The difference in dimensions(Size (L x W x H) 42 x 17 x 41.5 cm vs 34 x 14.2 x 41.5 cm)  seems a little odd as they both support the MTX QuickTrack™ System. I do plan to get an MTX trunk bag for it.
29" and 700c rims are the same diameter (iso 622mm). Primarily, the difference in width and length is to accommodate wider MTB frame stays and tires...I'd stick with the TA2026-B.