I've done a number of follow-up experiments with lavender in an attempt to improve/perfect it.
1) Added 2 tbs culinary lavender to previously described wheat recipe at beginning of boil, end of boil, or in secondary. Of 11 tasters, end of boil got the highest score, but they were all similar. The secondary definitely had a greater lavender aroma and flavour. The beginning of boil was almost invisible, and the end of boil had a very slight aroma and flavour.
2) Added 1, 2, or 4 tbs culinary lavender to the secondary of the above wheat recipe. The 2 tbs got the highest score here. The 1 was present but subtle. The 4 was quite strong- many thought overpowering, but my wife was happy with it.
3) All-grain stout (3# 2-row, 1# choc malt, 0.5# dark crystal, 0.25# each roasted barley and red wheat, mash 160 x60min, 0.5 oz Fuggles at 60 and 30 min, Yeast S-04) with 0, 2, or 4 tbs lavender added to secondary. The 2 tbs got the highest score and was _really_ interesting. The stout and lavender flavours worked quite well.
Summary: I plan to use 2 tbs in the secondary in the future. Planning to do the wheat and the stout with that amount of lavender as well as some lactose, since I think a little sweetness with the lavender would be fabulous.