dash lights not working

Gauge voltage limiter has absolutely nothing to do with anything other than the 3 thermal gauges it supplies.
The only part of the ground path left to service is the ground strap from engine block to firewall.
As for your positive side of the circuit,
11.6 volts isn't 12. Start the engine and you might see 13 + and brighter lights.
You need to realize there are only 4 bulbs for illumination in the panel. It never was quite as bright as the radio dial of floor shift bezel where a brighter and more direct type of lamp is used in those.
Sylvania #2825 is a slightly brighter than OEM incandescent bulb but... they aren't enough brighter to justify that expense after you already purchased the 194.
You may not be happy with LEDs either. Some are, some aren't.
For what its worth... the 2825 bulbs in my 67 rally dash looks fine at night but during day I can hardly tell their on. I should mention I've soldered a jumper over the dimmer rheostat so they are full on no matter where the knob is rotated to.