Inrush from powering all 6 at the same time will almost certainly trip a breaker or blow a fuse. And Meanwell specs indicate a primary amperage of 6.8 A on 115 VAC so if the supplies are operating near full load (6 * 6.8 = 40.8) then it becomes questionable if one could even have them not trip a breaker under typical powered up circumstances; single phase 120 VAC outlets in the US are either 15A or 20 Amp.
I would I think suggest creating 2 groups of 3 and try running these from 2 outlets known to be on separate breakers. That should get the full load down near or slightly below 20 Amp per breaker. Thermal delays in the breakers should enable one to get past the inrush. An alternative is to build into the primarys a means to power up the supplies one by one or commit to running them from 240 VAC.
Another point to consider is to insure that the wiring/cable from the outlet to the supplies is sized correctly and that it may be a good idea to have each supply fused. Although the supply should according to a Meanwell Technical Manual for their SPSs have an internal primary fuse, it is not easily user serviceable.
I calculate slightly different numbers, (4950 + 150) * .055 * .3 = 84.15 Amp. WS2811 type pixels? Not that it matters really but resistor or regulated?