I'm installing a new level 2 EV charger at our home, and just wanted to make sure I'm doing this correctly before turning the sub panel back on. We have a 200 amp main panel on the house, with a sub panel on the back of the garage that runs off of a 70 amp breaker on the main panel. There's currently no room for a new two pole breaker on the main panel, and I already had a 220v outlet on a 40 amp breaker for my welder in the garage, running off of the sub panel. This was all done professionally, but I want to try and save a bit of money and do the EV charger myself. Since the EV charger requires the same 40 amp breaker, I decided to hardwire the EV charger by splicing it into the welder's circuit. I've upgraded the whole run to 6 gauge wiring since it's about 70 feet from the sub panel to the charger, and also added a second 220v outlet closer to the front of the garage so I can move the welder around a bit more. They will NEVER be used at the same time. We're only going to charge the car during off peak hours at night, and I'm not much of a night welder. Main panel > sub panel > 220 outlet > 220 outlet > EV charger. I've tried to look up but can't find the exact answer. The QUESTION... The 220 outlets are NEMA 6-50 (hot-hot-ground) and the electrician installed it using hot-hot-neutral, with the outlet's ground terminal connected to neutral on the sub panel, rather than ground. I've got everything wired up and ready to go, but before I connect that last wire and turn it all back on, I wanted to understand why it previously went to neutral instead of ground, and if it needs to still go to neutral. Attached is an image of the sub panel if it helps. The other two-pole breaker is for a hot tub, but we're getting rid of it. Bottom left is the new 40 amp circuit with the 6 gauge wiring and the non-connected green, waiting for the proper home. Any guidance would be greatly appreciated.

Newbie Here..... Im looking to see what it would cost to set up an outside sub panel with 2-20 amp 220v breakers and a 20amp 120v breaker to run 2 circuits for solar panels with Enphase Micro Inverters and 1 circuit for couple of outside lights. The run would be 200 ft, so guessing 4 gauge aluminum with 60 amp breaker...would this be right and should I run 3 or 4 wires?