I second the advice from BFR and futbol. For current conditions (dry trail with virtually no snow), a 10 hour round trip is perfectly doable for a fit person. Just to add a few tips:
1) Navigating E-ledges in the dark for the first time can be confusing and even dangerous. As mentioned above, it is a good idea to study that section a day before (as a brief acclimating hike) and/or start around 4-5 AM to get some day light. There are plenty of YouTube videos that give you an idea what to expect.
2) IMO, the key to not getting lost on the way to UBSL from LBSL is to stay left after leaving the LBSL (some rock hopping will be required) and then stay high. Look for cairns. It gets less confusing when you reach the slabs.
3) There will likely be many variations of the trail right before you start gaining the Iceberg lake plateau. Again, look for cairns.
4) On the final ascent from the Iceberg lake, stay on the left (steeper) side instead of ascending the gully from the very bottom since the gully has lots of annoying scree. The use trail ascending the initial hill should be visible from the lake but it is relatively easy to get off route to much harder terrain when you reach the real rock.
5) When you exit the notch, the two alternative routes to the summit involve class 3 scrambling to the left and up (the final 400) or so called "easy walk off" that follows the less steep line around the final 400 (to the West) and then up. The latter gets little dicey in winter/icy conditions, but I personally prefer it for summer ascents with a heavy multi-day pack.
Good luck !
Last edited by Anton; 07/29/21 08:44 PM.