I think SRT/RAD setups are pretty situational. The grigri system you're using is probably great and works well for what you're using it for. I"ve always been from the school of thought that its better when gear I'm carrying can have many multiple uses(like your gri gri is in your system). A couple slings, cordollette, biners, ATC, and prusik loops have a lot more versatility to me so I prefer setups that use a lot of those kinds of things. Hell even small changes like carrying spectra webbing instead of nylon makes them more versatile for use as prussiks/etc. The majority of my SRT experience(and knowledge) is in rescue situations/training on rock, ice, or caving where you need to be able to make an efficient system using the gear you have.
That being said, I like using a texas prusik style setup. It's a classic crevasse self rescue setup that is adaptable to a lot of different situations and is simple and light. If oyu happen to have a mini ascender it can work great in conjunction throughout the setup.
There are some other folks on here with some different backgrounds that could give you more insight on things like rope wrenches, and other specific gear designed for SRT/RAD. I've played with some, but not to the extent any of the arborist guys here have. If youre interested in the more "mountaineering" side of rope systems I suggest picking up a copy of "Freedom of the hills" it is like the mountaineering bible.
