I suspect the main worries on your radar are, The Shingles and The Needles Channel, Portland Bill and Lyme Bay.
For info, the winds around here are predominantly SW although they have been swinging a lot over Winter. Now I think, Colin, Matt, Ed, Anton, Martin, James and Nick T would all agree to head out to leave the Needles to Port say about 100m at slack with an F3-4 max heading Sw until you clear the SW Shingles Marker, although with no wind at all, its a different matter. I can see the overfalls at the Shingle Bank regularly from the cliff top and from Hurst the race is predominant. Having said that I was out threading the Needles the other day with a double high tide and it was benign.
Portland is a different kettle of fish, some people say its a nightmare and others a piece of cake. I've only ever been round it twice in a boat, but seen it kick up several times from land, the race is out to sea a bit 5nm should clear it on an offshore passage. I've seen a vid made by Tom Cunliffe, albeit he's a sailor, but his advice on the inshore passage and taking it at slack, for me is spot on. Hold up in Weymouth (its about 50 nm from your berth in the Hamble so should be all OK) and try to get to Portland at slack, then head round on the inshore passage, both times it was better than expected. As you are in a stable Sessa though,
Lyme Bay can be either big or benign too, luckily I've only ever seen it calm so not really much help there. I've just plotted a direct course and its about 30nm form the Bill to Torbay or 53nm for an inshore passage, so not too bad.
Let's see what the others have to say.
