So far I've established this:
xtool:e:precomp:c128mb,t100p:zlib,lz4,oodle+srep:m 3f:a2+lolz:dtb1:dto1:dtm1:dtw1:dtd1:d256m:mtt1:mt4 :mc1023:gm20:fba4096
(XTool + SREP + LOLZ)
The LOLZ setup came from Entai44, which I am thankful for. I'm trying it out now on some small Indie games and it's running surprisingly well. I just hope the end archive can be read and decompressed by my installer otherwise there isn't much point carrying on.
Edit:
As we can see in this case, XTool made very little difference in file size (not that I expected it to in such a small game). Original size is 809mb (Untitlied Goose Game).