Well done so far and good progress. All too often I have heard that 90% of the carby problem is ignition. So as suggested start with good copper core HT leads and at least confirm that the plugs are good or use all new ones, then you have to look at condensor a high probable cause and last the coil.
Without a positive way to test the coil and condensor you are only guessing and that these can and do break down as they age so what might test ok on a multimeter can still be faulty under load or in working conditions. I got lucky once and bought a coil/condensor testing machine that was popular with lawn mower shops but they work perfectly well on all types of coils/condensors. IT actually puts a charge through the components and gets them to operating temps. I test them cold first and take note of the settings then heat and test again. What I thought may have been good got binned and what I thought was maybe going to be rubbish passed with flying colours.
With the Holley 350, from my failing memory, they are easy to strip and clean and the jet block is so good to check for blockages. Then the air mixture screws need to be thoroughly cleaned out and blown through with air. Check the main shaft for leaks is going to be the hardest thing to establish unless you test that before you remove it by lightly spraying some carby cleaner arounf the throttle shaft and at the base of the carby. If the idle rises you have a problem.
Setting the fuel height again is so simple by removing the plug on the side of the bowl and adjusting the nut on top of the bowl by undoing the lock nut and turning the screw up n down until the fuel just shows at the bottom of that hole on the side. Lock the nut. Like so many carbies start at 1.5 turns out from bottom on the mixture screws and watch your RPM and get max RPM then screw it in 1/8 of a turn and see what happens. NEw gaskets top to bottom will be a bonus as they possibly have dried out and may have a crack in them too,