The Sony Data sheet we have for the sld1236vl is limited. Thankfully at least it does give the ratings. Personally I don't think it is a good idea to drive these much over 160ma's if using fairly long duty cycles. 200ma's, and over I would keep the duty cycle under 10 seconds, and I would not go any higher than 250ma's.
I have learned the hard way running these for long duty cycles over 160ma's they don't last long. And I lost two when I peaked them at 400ma's and 500ms'a. Even though it was only for a second, they did not last very long after I did that.. :'(
The good news is I have found running the diode at its specified maximum cw rating of 130ma's, it is still an awesome burner. It will light an unsharpied match almost instantly at 2 feet away. And the beam is nice and visible.
Please note your mileage may vary as each diode tends to have its own personality even when they come from the same batch. And what I am stating is based on my own experience with this diode...