JB, Lari Ann on the Aroids Forum would be the one to ask for definitive direction about propagating your Philodendron. Nice having a hybridizer/botanist here.
Nipponanthemum nipponicum (Montauk Daisy) and Ajania Pacifica are both easy to root from cuttings.
The MD in this pic represent 1/3 of the cuttings from late June from 3 plants, all just stuck in a "mud" puddle and watered frequently. The AP cuttings are 1/2 of those from mid July, from 1 plant, with same "planting" method. Photo was taken 10/15/2010.
This pic was taken 11/19/2010