Yamaha DTXpress/DTXplorer/DTXtreme

I am very close to purchasing a DTXPRESS II and noticed, after 
searching this forum, that you all have been helpful in answering 
questions regarding expandabillity of the system.  

I wanted to ask you what you think would be the best/easiest way to 
add an extra tom and cymbal to the stock DTXPRESS II system. I would 
like to keep the unit realatively small so I would prefer not to add 
an expansion box or additional trigger module.

I was thinking I could add an extra cymbal (pcy65) and an extra tom 
(tp65) utilizing a split cable into input 9/10. Do you think this 
would work?  Or would you do it differently?

I really appreciate any help you can offer. 

Thanks much!

Tom