Part of the problem with introducing a "weak" section into your leader involves creating a hinge effect at that weak section. Your leader will stop turning over at that point.
If you put a heavier tippet on than your leader, the leader will also stop turning over at that point, altho the reason behind it will be different.
As your fly line and leader turn over in the cast, each little bit that turns overuses a little bit of the energy of the cast. A heavier mass requires more of the available energy than does a lighter one, so your fly line is tapered to use less energy where less is available.
Most leaders, whether knotted or not, are also tapered for the same reason.
Introducing a sudden change in diameter or weight can seriously mess with your presentation. (This is also why I don't like using splitshot on my tippet. Well, that and I keep losing the shot
)
Your best bet in the situation you describe is to use a heavier leader, designed to accommodate the tippet size you want to use. To cut down on the cost, you can tie your own out of various weights of mono. There are an abundance of leader calc programs on the interwebs.
Whatever you come up with, take it to a pond, swimming pool or field and cast it a few times to see how it works and to get used to it before your trip. It is frustrating as hell to try to work the kinks out when you want to be fishing.
The exception to the tapered leader is using a piece of, say 8 lb, mono as a leader for casting poppers and big bass bugs. There you have to adjust the length of the leader to suit the fly. If it "plops" at the end of your cast and you don't want it to, add to the length until it quits. If it won't lay all of the way out, shorten the leader to about where the cast dies.
Good luck, and be sure to post a few pics after your trip!
Kirk B.
