Source: Conn Copas (Conn.Copas@dsto.defence.GOV.AU), Lambic Digest #951, 9/30/96
As a first guess, I would essentially brew a tripel, but cut all ingredients back to give an OG in the 1050 or so range; hopping and spicing should be reduced also.
Haven't tried the Witkap pater Tripel, but I'm fairly certain the Witkap pater Stimulo uses honey, which might be worth considering. Otherwise, if you want a delicate brew, I would second the use of glucose (as opposed to sucrose). At the risk of bringing the wrath of Belgo-philes down upon my head, I would question the use of orange peel here. Many of the Wallonian brews are way over-stated in the spice department IMHO, and that includes favourites like La Chouffe. If you are heavy handed with the coriander then it is not a big problem, because it will blend in with maturity. The citrus nose, however, just stays there forever, and often dominates the yeast as far as I am concerned.