I did some testing with 32 vs 64bit renoise as my plugins are 64bit, but now all my plugins are wrapped and bridged.
If I use 64bit renoise, it will bridge plugin (->64bit) + same in 32bit version (->32bit).
I am on OSX 10.6.8 in 32bit boot mode, but Snow Leopard can run 64bit apps in 32bit mode.
edit. oh and latest 2.8.1 versions of renoise.