You must recompile the library or at least printf_large.c. You don't need to use --model-large though you can easily run out of internal memory without it. There is no precompiled library with both --model-large and --stack-auto.

Easiest is to copy printf_large.c to your project directory and include it in the sources to be compiled and linked. Then use -DUSE_FLOATS=1 or adapt the source itself. When explicitly linked it will override the version in the library.

If you have real external memory and want to use --model-large and --stack-auto you need to rebuild the whole library with those options.

If you do not have external memory, then I recommend to rethink your strategy (always a good idea). Do you really need to print floating point variables? Do you need to use floating point at all? I would not recommend it unless you had an 8051 on steroids with a good dose of xdata and your development time is costlier than runtime (low production volume).

Maarten