The 2.6 m will have noticeably more power as the wind picks up. Enough power to scud down wind on the sand when winds are strong and a good work out.
It would be my choice.
The 1.8 will fly very fast through the window and turn very fast compared to the 2.6m. It won't over power you unless the winds are extremely strong.
Short little spurts of power. Sort of too small for 195# if you want to actually feel any real power. Unless the winds are very strong.
Look in to Revolution kites when you look at framed kites. By far the most fun and challenging to fly!
Kites: 2.5m Profoil , Quadrifoil XL kitesurfer, NPW 5 Danger.
Flexifoil: 1.7m Sting, 4.9m Blade 3, 9m Blade 2.
Flysurfer : 19m Speed 2 SA, 7m Pulse
Peter Lynn :18m Phantom, 15m Synergy, 10m Synergy, 1200 Farc, 460 Sarc, 130 Tarc, 5m Peel, 4.2m , 6.4, 8.5 C-Quads, 3.5 LS2 single skin.
Rides: Flexi / P.L. Frankin'Buggy , Shaped + straight skiis, sand skis, Coyote blades. Core 95 ATB. RKB R2 ATB .
Ken (K2)