You'd really struggle to see anything with a 12/13 filter in your visor for sheet metal TIG welding. If memory serves me right, a 9 filter would be what I use when welding 0.9mm (about 35thou of inch) stainless with less than 30A.
If your visor filter shade is too light, your get the message gently because you can't see right when welding or when you take the visor off - but that is due to slightly too bright light and not highly dangerous UV, which is stopped by the glass of the filter, regardless of how dark / light it is.
But yes, if you are doing sheet metal with any normal TIG, you will want a 9 or 10 AWS filter. Your current choice is way out.
With TIG you have the advantage that with being a very clean process you can keep your visor cover slips and the filter itself spotlessly clean. You should actually have a lovely relaxed full view of the welding area - you should be able to sit back and enjoy the experience.
Some additional points as you learn to fly TIG:
I remember as an absolute newbie getting all crossed up including in trying to see what's going on. Was especially getting tangled up trying to fillet weld. Fillet is easiest for most processes (MIG, stick) but more difficult with TIG. With TIG in fillet, you are trying to get the torch into the corner, the shroud is blocking the view, you have to get the tungsten in close, you have two surfaces to crash it into, you have to get the filler rod under the tungsten without crashing the filler into the tungsten, if you overfill and the metal flows fast in a big front it can wash up and touch the tungsten. It can get very exasperating. But it will come together with practice. And all with cricking your neck trying to see what's going on under the shroud.
With TIG, it's so clean you can sit relaxed at a table, so easy to put in practice.
The advice "with TIG you weld at the lowest current at which the weld can be run" will serve you well. The experienced folk may be able to control with a bit more power on for fast run speed, but for you, probably take pride in really neat small cool welds run quite quickly with a small heat input (in kJ per mm of weld). The other advice I would offer myself, something which worked for me was "let the machine look after you; control the amps on the machine so you floor the foot pedal and just control the starts and stops". When you know what a good weld looks like, then you can give yourself "headroom" with the current setting on the machine and control on the pedal. As I said - that worked for me. Was controlling on smaller and smaller currents as I improved my technique, taking of an amp or two at a time and getting able to control delightfully small neat welds.
At the time I was learning TIG, I kept a running diary
exasperation at times and my elation at passing standards are the point I am making.