you might consider using improved climb + bleeds off with assumed temperature. (There are companies who forbid this, most sensible ones don't though.)
The idea of using improved climb and/or bleeds off is because the normal thrust setting will not be enough to haul your heavy weight off the runway within runway and climb limits. Thus you have already tried maximum thrust and found it not enough. Why then would you use the performance enhancing techniques and then use assumed temp? That's like driving and accelerating with your foot on the brake.
Further: why use anything other than normal when NOT at a high weight? I don't get this use of improved climb as the 1st choice. There are many companies that don't have these charts because they are unnecessary in their network. They use extra thrust at higher weights. I don't understand the use of improved climb unless at high weights. The same applies to bleeds off. Why not KISS.