Two points I wanted to clarify based on some great feedback here:

1. My last post is not recommending that lido with epi be used – plain old lidocaine is much more easy to manage and use safely. Rather, lido with epi is not a one way trip to losing your finger, as it often is regarded as in the dogma of biohacking – while it should be treated cautiously, it is not necessarily contraindicated for digital work.
2. Lidocaine with epinephrine provides its own hemostasis, and its use makes tourniquets unnecessary. Using a tourniquet AND lidocaine with epi, or some other hemostatic method, can indeed lead to ischemia as evidenced by issues other magnet implantees have had — no reason to mess with something that works just fine without epi.