Surface fishing casters for trout

[courty]

Hi,
I fish a reservoir for rainbow trout. I can see them feeding on the surface, and they wolf down the floating casters I throw in, but seem to avoid the one with the hook in it!
Anyone have any tips to improve my presentation? I usually use a bubble float attached with a swivel link and two stopper shots 18" from the hook. The line is 5lb mono, hooks are usually no.16 and the caster or two cover the hook in the traditional method. I use either a small piece of cork on the top of the hook or just above, or a red rubber floating grub to make them float. I've tried without a piece of floating stuff by the hook, but it just sinks and I rarely get bites. I've never used any floating grease on the line.
I've considered making fake casters out of cork or balsa wood to put on the hook with a real one, but wouldn't the paint/wood stain/varnish give off the wrong odour?
Is there something else I can do, or do fish "just know"?

[courty]

OK ladies and gentlemen, no replies to this post. Either no one has a useful answer, or there's a big secret people are keeping to themselves.
Today I had the same problem. I experimented, and found that a caster on a tiny hook (22!) on a 1.1lb line had a bite straight away, but the line broke immediately. So it appears to be a question of scale.
To present a caster that floats like the ones I throw in, the hook has to be small enough to be hidden inside the caster, but big enough to hook the fish. The line needs to be as inconspicuous as possible, but strong enough not to break.
So here's the challenge. What line is strong enough to land the fish (I take it I'd use a leader and play the fish for a bit longer) and which hook do I use?
Finesse is everything in this game. ANY suggestions would be gratefully received.
Courty.

[Greenheart]

You could try using slightly stronger Flourocarbon hooklength. It's supposed to be incisible in water. I'd opt for something around 4lb. Use a soft action rod to soak up any agressive takes.

[courty]

Thanks for the suggestion, Greenheart. I haven't tried it yet, there's been too much month for my paycheck this September.
I tried some ready tied kasama hook lengths at 2lb 12 and it broke very quickly, even on a fairly soft rod. Would having the reel clutch set really lightly help do you think? Or is a break inevitable for 2lb trout no matter how carefully it is played?
I'll definitely try fuorocarbon. I've had a quick read on various sites and there are all sorts of debates about which knots to use, how it compares to hi-tec line that is thinner than FC, etc etc.
Will the adventure ever end?

[Fish8myfly]

yep flourocarbon is your best bet and getting leader sink to hide it even more. 4lb up to 7lb would be best

[courty]

Thanks Fish8myfly,
unfortunately it will have to be next season, as my local water has closed for winter. They weren't feeding on the surface in the cold weather anyway, so let's hope Santa brings me something good for next Spring.
The leader sinker you mentioned...would that put more pressure on the bait that needs to be very bouyant, and would it snag on the trout as they swarm about gobbling up the freebait?
I guess I'll have the answer for that next year. I will be brave and try fishing on the fly next season too, so I'll have a whole new bag of questions.
Cheers for your answer,
Courty.