IMHO... If the figures for the flap30 LE retracted are not published do not do it, if Boeing wanted you to use this configeration they would have supplied the speed, at the subsequent enquiry you would be crucified for makeing up your own speed, also what speed would you use?
Only one gear leg has failed to lock down, two are down and locked, therefore cannot use 30flap/LE retracted as Boeing does not cover this as a landing config. or supply these speeds.
I feel the flying and threshold speed for the flap/Le config. has priority. There is no need to improvise outside of the QRH in this case as it is covered by what they left out.
I thought multiple failures were nolonger allowed in the simulator anyway and you could have aborted before V1 for a burst tyre.
I found abandoning with tyre failures on one side, be prepared to use the nosewheel tiller positively (or call for its use if not fitted your side) as you run out of rudder pedal steering and directional control to stay on the runway centerline.