I set this up for each of the 12 positions to show a range from zero to "X" units of time. So your first answer must have "within X weeks." I know it's a hedge, but I wanted an elastic perspective that shows the "outside" estimate as the starting point. The 6-card line is intended to get more specific within that range.
One way I can think of to pre-select your initial time-frame, as I mentioned in the original post, is to do a normal spread first and then take the outcome card as the significator for the timing spread. The element of the card (and all of the cards have an elemental association, whether through decan, planet or zociacal sign) would give you a first cut at a time-frame: Wands as days, Swords as weeks, Cups as months and Pentacles as years. (This is my own take on it based on elemental "humours:" choleric, sanguine, phlegmatic and melancholic.)
The main problem I always had with the conventional approach is that for most matters, Pentacles as "years" might as well mean "never" (although in fact that's sometimes the truth). I was stuck "backing down" to a rational time-frame anyway, just to have the timing make some kind of sense, so I thought it would be good idea to try "building up" instead.
Although I still think "intuition + reason" is as good a way as any to settle on an initial time-frame, there are other more random ways I can think of. If you include "hours" in the mix, you could roll one six-sided die so that 1 spot = hours, 2 spots = days, 3 spots = weeks, 4 spots = months, 5 spots = quarters, and 6 spots = years. You could then give that the "giggle test" to decide whether you should adjust. Or you could get one of those special RPG 5-sided dice.
My initial suspicion was that this method would routinely "under-shoot" the target, pointing to "days" when "weeks" would be more reasonable, but it looks like your case went the other way. But it's only one data point.