z88dk or sdcc ?

Not sure that z88dk is going to work for me. Concern about how well the linker output can be controlled and how well it works for rommable code:

Z80 will need special consideration for placing startup code and interrupt vectors. Not seeing anything in z88dk akin to an ld script where sections and memory placement can be specified.

Noted that z88dk supports an asxxx assembler output mode, so it could work better to assemble select modules in C and integrate them with my existing asxxx project.

sdcc looks promising based on based on ASXXXX and targets many micros including Z80. Some useful Z80 specific info on the wiki and good documentation. Article on ColecoVision development.