Regarding foil caps, if you're thinking about the type that could be formed around a pencil (for instance), and then slipped over the pistil and tightened, I never use them. I'm sure they work great for flowers with large pistils, but I am usually working with much smaller flowers and more delicate flower parts, so those "elephant noses" wouldn't work for me. This is what I do, and with a little innovation perhaps, it will work on cut styles:
I cut small rectangles of tin foil of various sizes so I have a range to choose from when I am out in the garden with various size flowers to pollinate.
After I have actually done the pollination, a rectangle gets folded in half and slipped over the stigma. An additional quick fold, crease, crinkle... (however you want to do it) to secure in place will finish the job. Too much futsing will weaken the folds/creases/crinkles and they won't hold. If this happens, just try again with a new rectangle. No big deal.
This particular flower (below) had a large stigma to grasp around, and it is an upfacing flower, so attention to detail wasn't necessary.
For down facing flowers, it is a bit more difficult, and with many species the stigma is hardly larger than the style itself. Steady hands and practice will help a lot. You will develop what works best for you. For a cut style, the tiniest dab of glue, applied with a toothpick to the style away from the cut end, that will make contact with the foil, should keep it in place. I've never needed to do this, but I can't imagine that it could hurt anything. Just be gentle.
-----------------------------------------------------------------
In fact I've never tried a cut style pollination. Though I've always been at the ready, the need has not presented itself, or so I think. The main reason for this method is to shorten the distance a pollen tube from a pollen grain must grow (down the style to the ovary) for fertilization to take place. It is (apparently) a known fact that using a short styled parent A for pollinating a long styled parent B often is not successful because the pollen from the short styled parent doesn't grow a pollen tube long enough/fast enough to do the job through the much longer styled pistil of parent B. The other reason is thought to be that the stigmatic fluid (found only at the stigma) might have a blocking effect for wide crosses. But in other cases, dabbing stigmatic fluid on the cut end of a style is sometimes recommended in
increase success.
At any rate, I don't see any advantage to cutting the style just below the stigma, as opposed to half way down. Perhaps you have some insight on this, Lorn? Me, I would always cut half way down to hedge my bets.
I think we'd all be interested to know what parents you've tried, Lorn, and the successes/failures in those respects.
