Steve and a few others will likely provide better answers, but in the mean time I offer the following.

I guess there is no way to say for sure, but based on your 1000'/hour I would guess your times are conservative. I did the same route you are considering in 2012, and my times as follows:
2 hrs to LBSL
1.5 hrs to UBSL
1.5 hrs to iceberg Lake
3 hours to summit, via "final 400".
5 hours back to car via main trail, including a stop at S/B 22/23 for water.

I had previously hiked up to LBSL several times, so knew where I was going up to that point. I recommend you do this the day prior to your hike. This will help when you start in the dark, and is also good for acclimation.

These times going up included a couple of 20 minute breaks for snacks and water refill, and perhaps 15 minutes off route.

I would guess your time will be faster if you are able to stay on the route, and provided you are properly acclimated, and not suffering symptoms of altitude sickness.

Just for reference, the fastest known time going up is less than 2 hours, and roundtrip around 3 hours.

There could be snow in mid June, but suggest you simply watch trip reports for more current info as your time gets closer.

If there is still snow on the "easy walk off" I would personally prefer the final 400 (assumes a path clear of snow). A slip on the easy walk off would be painful.

Good luck. Post a trip report when you get back.

John

Last edited by John Sims; 04/07/16 03:16 PM.