I think in the ideal situation I would like to get my meal bolus in and started somewhere around 15 minutes before I start eating. This is assuming I'm not low (or heading low), not dealing with any delayed digestion (don't think I am yet), or any other weird situation.
This has been recommended as long as I can remember - back in the days of bolusing with Regular insulin, and now using the faster acting insulins. The time was different though. Back with Regular insulin we were told to bolus 45 minutes before eating.
Getting this timing down has always been near impossible for me, and since the consequences of not getting that meal are pretty heavy - such as a sever low blood sugar, I have always bolused when the food is either a certainty or is actually right in front of me.
But the times where I can get that insulin in my system and working ahead of the food by a few minutes, I have very nicely matched curves - closely matching the digestion with the peaking insulin, resulting in spikes that are very tolerable and that are quickly back to normal.
But again - the potential for disaster is HUGE if for any reason that meal is delayed or drastically different than what you planned for. So that part of it scares me off most often.
Another approach that I've seen, but not tried, is to take a partial bolus up front, then finish it off at mealtime. I guess that way if something changes you are trying to catch up to a much smaller bolus rather than the entire boatload.
I think the primary reason I've not been very successful at this is that most days I can hardly get my act together enough to know what will happen 15 minutes from now.
Not to mention, I think it adds yet another level of complexity to the already painstaking tasks of doing all the diabetic stuff that surrounds mealtime. And that kind of ticks me off.
This is practically impossible for parents of young D'ers - where you don't know what they will eat until it's down the chute!
But what about you adult OC'ers? How many of you pre-bolus? Do you do the entire meal bolus beforehand, or just a portion? How far in advance do you do it? Does it matter for you what type of food you are eating, and do you adjust the lead time accordingly? Does it make a big difference for you?
And lastly - how the HELL do you keep track of it all?!! Do you pull a modified "flava-flav" and wear a kitchen timer medallion on your gold chain? "Ding! - time to eat!"