Work out the ground bearing of Alderney/Cherbourg from whereever you start and sail to that heading. Do not compensate for cross-track error due to tidal set until about 10M off, when you need to look at the almanac and your track and deduce a new course to steer in the normal way. I.e. you will have confirmation of the tidal rate against the almanac, from your track. All cross-track error will be due to tide.
This works because the crossing will take just about 12hrs, one ebb and one flood.
Oh, another thing... leave very early in the morning, or at night if you know your take-off area well enough, as you will end up looking for a berth in Braye 12-14hrs later, and you don't want to do that in the dark!!
I am taking it for granted that you have read the pilot books and almanac, and are aware of the tidal situation at Braye or Cherbourg. You must aim to be up-tide of the entrance, and be aware of the transits you are looking for. As long as you have them clear in your mind, you will be OK, there is nothing to worry about except fog, in which case stand off, sailing in clear water away from shipping lanes, until it clears, unless you have radar. GPS will get you in, but won't tell you if you are going to hit anything, and if your GPS chooses that moment to go on the blink, I would not want to be in your boat (unless, like me, you have a spare GPS).
This weekend, the channel may well be lacking in wind. In that case it might be a bit rolly. Keep your main up, even if you motor a lot, to stabilise a bit - and take stugeron anti-s/s tablets, even if you are not normally sick. It's more optional in the case of the wife and kids, but you need to be 100% sure you will be OK. Next crossing (when it is not all unknown and new, and you are sure of your first mate's ability to navigate and keep watch even if you go down with seasickness) is the time to go macho and not take Stugeron.
Try both places (Alderney first to avoid potential customs problems on return to England). Unless you only plan to go ashore once or twice I suggest you take your dinghy and outboard or the taxi costs £1 per head each way ie if you all go ashore 3 times each day it will cost you £24!
Alderney has strong tides so be careful when you arrive. The harbour is sheltered from most directions except NE when you will roll like a pig unless you anchor (£2 per night as opposed to £11 on buoys) well away from others and use your kedge to keep your bows into the swell.
The best meal we had there last week was at the Braye Chippy - inexpensive and excellent quality.
Take the boat trip around the island, it's the best value £12 you can spend.
Leave for Cherbourg 2.5 hours after low water. Stock up with booze at the hypermarket and take your passport if you intend to use plastic. The wine and beer company (in the same building) sell a good range of British beers at less than half UK prices. Spend about £65 with them and they supply a taxi back to the marina, so you can get all your shopping back fairly easily.
Have a great time - we certainly did.
You don't say the dates but if you are going over on the weekend of the 21/7/001 i will be going to cherbourg as well. it is always safer to go with 2 boats rather than one.
i wil be leaving yarmouth on the Sunday or monday early morning. So if you want company let me know..and Cherbourg is much easier to get to and you can get a good rest after the trip unlike Alderney if the wind is wrong.