With the finger crossed I will start tomorrow a project in mkiv

but I would like to test what Hans, Taco and others are doing, at least to help find bugs for the Right to Left typesetting.

It's important, so
I write how I setup my minimals on a linux box
1) mkdir -p /opt/luatex/minimals-beta
2) cd /opt/luatex/minimals-beta
2a) Now put here first-setup.sh (see contextgarden.net/minimals)
3)  ./first-setup.sh
3a)If there are some errors due a luatex version; hit return until the end
4) cd tex
5) . setuptex
5a)Now, if you have compiled luatex from svn, put it into texmf-linux/bin
6) context --generate
7) context --make
7a)not errors  anymore, I hope.
8)Every time I start a mkiv session
I do
cd /opt/luatex/minimals-beta/tex
. setuptext
as first step
to ensure correct initilizatione of env variables.
9a)context --generate
9b)context --make
to unsure a clean session.
10) always use context to make pdf; ie test your file with
context basic-test.tex

If you open first-setup.sh and change this line

mtxrun --verbose --script ./bin/mtx-update.lua --update --make --force --engine=all --context=beta --tree=$PWD/tex $@
in
mtxrun --verbose --script ./bin/mtx-update.lua --update --make --force --engine=all  --tree=$PWD/tex $@
and then
1) mkdir -p /opt/luatex/minimals
2)...
you can then end with a minimal installation