Finally figured it out last night!
Using image: nvidia/opencl:devel-ubuntu18.04
Installed the latest boinc (7.16.1). 1070ti is happily crunching Collatz at 7.3 cents an hour, at least until I get outbid. I was not able to figure out remote.
I have the following in /root/onstart.sh, since when the instance comes back up after a higher bidder stops/destroys theirs, I can start crunching again.
/etc/init.d/boinc-client start
Does that look right?
We'll see how this actually holds up, since I'm only 12 hours in. You can also get on demand (so no bidding involved) instances.
1070ti seems to be holding right around 410-420 seconds per WU with optimizations, about 35-40 slower than my 1080.

How big of a difference do the RTX cards like 2070 and 2080 actually make over the 1070, 1070ti, 1080, and 1080ti? 1080ti seems to still be a very sexy card all things considered...I guess it makes a difference on what project you're using and what parts of the gpu are being stressed the most. Not always about clock speed.