PDF Creator Pilot supports the following page sizes:

Name	Dimensions	Value
pfUserDefined	Defined by user	0
pfLetter	8½ × 11 in	1
pfA4	210 × 297 mm	2
pfA3	297 × 420 mm	3
pfLegal	8½ × 14 in	4
pfB5	182 × 257 mm	5
pfC5	162 × 229 mm	6
pf8x11	8 × 11 in	7
pfB4	250 × 354 mm	8
pfA5	148 × 210 mm	9
pfFolio	8½ × 13 in	10
pfExecutive	7¼ × 10½ in	11
pfEnvB4	250 × 353 mm	12
pfEnvB5	176 × 250 mm	13
pfEnvC6	114 × 162 mm	14
pfEnvDL	110 × 220 mm	15
pfEnvMonarch	3⅞ × 7½ in	16
pfEnv9	3⅞ × 8⅞ in	17
pfEnv10	4⅛ × 9½ in	18
pfEnv11	4½ × 10⅜	19

All other page sizes may be set using the PageWidth and PageHeight properties.