usually, multi-fx' sucks your tone big time.
in my case i cascaded a gcb95, bad monkey and a ds1 to my zoom g1. since the function of my g1 is to provide me with modulation, reverb, eq and delays, the setting of my g1 on the first patch (A0) is usually reverb fx only. this patch serves as my bypass mode just to give me a good ambiance.
next patches (A1....) with have delay, eq, modulation fx, reverb, etc.
but if you really want to avoid the tone suck coming from your zoom or whatever multi-fx unit, just use a true-by pass looper.
as for me, the above settings works naman.