The Turbo Switch Grip is pretty easy to install in my opinion.
I've been using it for about 4 months now, and ive drilled alot of outter sleeves and 4 different inner sleeves.
Drilling the inners is just as long as drilling in any regular slug, it just takes an extra 30 seconds to drill and knock in the outter sleeve.
The drill depth for every outter sleeve is about 2 3/4 inches, and the outter sleeve is marked at the top with a white line, you just need to knock it in till that line... the depth is a constant. Just knock it in with some slide powder without glue to see if the depth is right... pull it out and then glue it.
After have inners drilled i find it faster to drill balls, because all i have to do is drill a 1 1/2 hole a certain depth and there we go... i don't have to wait for my exactacator or custom thumb sleeve to cure.
But, like everyone is saying, its all about personal preference... i think its a neet tool and it is very useful, because even exactacator thumbs vary one from the other a little...
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Mark Buffa