if you use an Ipac, you don't need any admin buttons. Start+Down is pause, Start + Right is Tab , Start+ Left is ENTER , and start+up is ~ (access volume control, cpu speed control etc in MAME) and P1 Start + P2 Start = Escape
the SF+Neo Geo Hybrid is my preferred layout , since it lets you play all the SF style and NeoGeo style games, and provides a great run button for the MK games that need it. Also, A,B,C of the NeoGeo layout work well for games like NBA JAM, Open Ice,etc