Quick advice for dry-hopping and racking to secondary

Dry hopping is one of the cases where I use a secondary. By dry hopping in primary you get interactions between the hops and yeast that I don't care for. I tend to dry hop in the serving keg and the dry hops stay in for 2-3 months. There is no problem doing that.

I use SO4 a lot. As you seem to know, its a quick fermenter. You might want to add your hops a little sooner to get some of the O2 scrubbing potential as the yeast are finishing up. Maybe Monday is a better choice.

Dry hopping then in primary is required. I'd let it go a full week from that point. If possible you could start a cold crash which would help bring some of the hops down if you used pellets. If you are using whole hops then they won't settle but they are easier to rack from below them.

Dry-hopping in primary is fine. Many people don't rack to a secondary fermentation vessel anymore unless they're actually adding additional fermentables. In fact, dry-hopping before primary-fermentation is complete (even at high krausen) is sometimes recommended.

In terms of timing I've seen many different recommendations, generally in reference to time before packaging (bottling or kegging). Somewhere between 3 to 7 days before packaging seems pretty normal. Some people fear that dry-hopping for longer (7+ days) can contribute to a grassy flavor in the final beer and err on the shorter side.

In a Brulosophy exBEERiment they tested the differences between short- and long-dry-hopped beers and found that though there seemed to be noticeable differences it was more a matter of preference than anything. Maybe the results there can give you some hints as to how you might want to go based on what you want out of your beer.