Chris is right. On some limestone you’ll need Oxalic to neutralize the SH. Not all, depends on where it comes from. Some has a lot of iron in it,and it’ll leave it kind of orangish in color if you don’t. This building doesn’t look like it has much, if any, so may be ok not using.
You can softwash with your 12v or whatever, going to take several coats probably on the bad places and probably at least some pressure, like with a shooter tip. Just prewet windows and don’t let mix come close to drying on those frames.
