Not sure if you are targeting squirrels as a commercial removal job, or simply trying to eliminate some from an area. Here in Illinois, we can't use any exposed body-grips for squirrels under the nuisance wildlife removal regs. However, I don't have a problem with that, as I have found the fastest way to catch a high number of squirrels from a structure is with small cage traps set near the primary entries (possibly combined with one-way doors or one-way multi-catch traps). However, I'll always trap a coupe days BEFORE installing any one-ways, as I've seen too many times the doors will cause them to chew out (around the doors) or chew in (again, around the doors). Catching the bulk of them before they get spooked or driven away temporarily due to the presence of the excluders helps insure you actually remove the "guilty" party from the site and minimizes your chance of having the problem show up a couple days after you "think" you are done.