Hi Lastchance,
The strung hackle I described above I used to buy from H&H, although I have bought strung hackle from other sources including some fly shops has been for all intents and purposes, the same.
That strung hackle is big enough to stick our from any chenille I have ever seen. On a #4 hook, unless the chenille is so large that it will hide the point of the hook, the strung hackle would stick out much much more that the chenille. In fact some of the individual barbules are probably 3/4 inch long, or maybe even longer.
This hackle is radically bigger than what you are describing as the minimum size.
It almost sounds like the hackle you have is something like a Metz micro barb saddle, which is really designed for #10 or #12 and smaller dry flies, not bugger hackle.
What brand and product name of saddle hackle have you been looking at?
The problem I have had is finding bugger hackle small enough to tie say a #12, and finding big hackle has never been a problem.
Thanks and regards,
Gandolf