Well i use 5-6-7lb fluoro from diawa and wychwood its nice and supple, the 5lb is good for single flies and 6lb with 7lb droppers for a team, but if you used the said lines with fulling mill use the mill for droppers as its stiffer

But dont get the 4lb in either for some reason its ****

Otherwise there are some very good monos out there , with very low diameters, dont be fooled by claims that fluoro is invisible to fish

and you wont be ripped off

Gaz
Are you using a 2 or 3 turn knot for droppers, and silly question are you using the dropper one away from yer butt? i cant see why 5lb would snap, remember fluoro dosnt have the stretch of mono so if yer tight on the line then perhaps a snap could occur, ive had 7+ nutty fish on 5lb with no problems , but when using teams the knot has to be right, ive found a 2 turn with low BS fluoro under 5lb and 3 turn over that for droppers, but more to do with the different thicknesses of the lines you attach together not so much breaking strain.simple thing is to test yer knots before going fishing with a weigh scale and see which knot works better2-3 or even 4.Gaz