If Tila tharpanam is to be done as Hiranya rupa for Darsha and Sankramana tharpanam-s, what must be done first? Are the procedures the same for both? Or for Sankramana, is Hiranya rupa done first, and for Darsha shraddha, is Tila tharpanam done first before Hiranya rupa?

If one intends to perform Hiranya shraddha, tharpanam must be done as a part of Hiranya shraddha. In this, there are no differences between maasa pravesha tharpanam and darsha shraddha. One must perform sankalpam with “hiraNya shrAddhAnga tharppaNaM kariSyE” and do the tharpanam. There is no question of which comes first.
Besides Hiranya Shraddha, we do “darSa shrAddha pratiniti tila tharpaNaM kariSyE”; this is different.