buildworld wrkdir, ignore error & single-user questions

[Beeblebrox]

I have several trivia questions.

1. I build 3 separate worlds (Host, Jails, Poudriere) with different src.conf settings (SRCCONF=file.conf). Is there a way to specify absolute work-dir path instead of relative? For example:
for host, "# make buildworld" goes to /path/obj/path/git/src
whereas, "# make buildworld TARGET=i386" goes to /path/obj/i386.i386

So I'd like all world builds to go to /path/obj/ and also set custom sub-paths such as:
"# make buildworld SRCCONF=jails.conf WRKDIR=/path/obj/src.j"
"# make buildworld SRCCONF=poudriere.conf WRKDIR=/path/obj/src.p"
What would be the correct syntax for above?
I doubt it, but any easier way to accomplish the above other than shell script?

2. Kernel is drm-next, and dmessg gets flooded with this error
[drm:radeon_vga_detect] VGA-1: probed a monitor but no|invalid EDID
Is there any way to set stdout to ignore or dev/null this flood?

3. Dropping to single user always asks what shell to use
"enter for bin/sh or path for shell". Is there a way to 
a) change default shell for single user 
b) just go to shell - no confirm
c) even if I enter /bin/csh at the above prompt, still goes to /bin/sh, I have to call csh from sh to get a decent shell.

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HardenedBSD_amd64_12-Current_RadeonKMS
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