Therrin

I used to regularly use a prussik as a backup with a normal descender... never two descenders together.

Looks like a smooth setup though, I agree with Ekka on that.

Little redundant maybe. Are you worried about the descender breaking? About not enough friction on the line? About the cam-lever braking on your Petzl 'stop' descender?

I've stopped using figure-of-8 descenders all together except for backup use. Tired of having ropes all twisted up.

I use a BMS rack now.
- easy to lock off
- doesn't twist the ropes
- can handle up to two lines at the same time


Using the Petzl 'stop' descender, with a prussik/hitch backup... you should be just fine, and that combo won't twist the rope at all like your figure-of-8 will. Lighter weight too.
- can add or subtract bars to change the amount of friction
- rated to 20,000 lbs

Using all three bars, with just my body weight, I hardly go anywhere. Don't even have to use a brake hand, it just slowly lowers on its own. Using 2 of the 3 bars is just right... one bar gives a quick descent, but needs serious attention on brake hand and a glove.

Just thought I'd mention it since alot of you arb folk aren't familiar with racks.

__________________
Ken Fessia
I.T.S.A. Tree Service
(661) 916-4703