Yamaha DTXpress/DTXplorer/DTXtreme

I just purchased a DTXPRESS III tonight, however, it won't get here 
for another week probably.  Between now and then, however, I'm 
trying to find out as many details as I can about what it will take 
to get everything working good on it when it gets here.  

One thing I need to ask of those of you who also have one is, I 
realize that a monitor system is probably the best way to go for the 
system, however, I can't spend any more right now and until I can 
afford to buy a monitor system for it can I use a powerful guitar 
amp temporarily, or not?  I have two, I have a Marshall full stack 
with a 150 watt 4 channell and dual 4-12 cellestion cabinets, and a 
Randall combo 100 watt w/2-12 30s in it.  Would it be ok to use 
either one of these amps?  The Randall is probably the one I would 
choose to use right now since the Marshall will be getting use from 
a guitar most of the time when I'm playing the drums.

Any way, if someone has tried using power guitar amps in place of 
monitor systems to amplify their DTXPRESS III successfully, please 
let me know, what you're using and how well it works, will you?  

Thanks,
Glen