Since no one has replied so far I will give you my thoughts even though its been a fair few years since I spent much time over there.
Mana, easy enough to get out of from probably about half tide on an H28. Go north of Mana Island. Tides aren't such an issue going that way as but nice if they are helping you. Fishermans rock in the middle is an issue, deep enough butvsome rips around it.
is the biggest issue, typical Nw makes it not much fun.
You can go wide outside everything including very wide on Stevens Island. Sailing overnight for a fast trip, or hop around the coast say across to port gore (watch Cape Jackson tides), or punt rails, port Ligar or Catherine Cove on Durville Is and either through french pass or Stevens passage
(watch the tide here, its brutal, 8 odd knots at times. Best hit them near slack water
, or at least with only an early favorable tide.
From memory the Nelson/Tasman bay area misses the worst of the southerlies that can whistle through Cook Strait. But it can still cop a good southwester. The seabreeze can blow at a good strength in summer. Port Hardy and Greville hbr are neat places and a good jump off point.
Across to Adele island is always lovely, and Torrent Bay, is pretty well all weather
, though it can get pretty nasty in a strong NE. Plenty of other nice spots along that coast. Point Separation gets a bit bouncy at times, but not to bad.
Tarakohi didn't have much in the way of facilities back in the day, but was secure enough. Probably much better now. Should be plenty of good advice around Mana.