For what it's worth...I just did this on my jeep. (master cylinder went bad- fluid on the firewall.) Your slave is not leaking on the firewall, I promise you that.
1.) Buy the cheap one, it'll be fine. (got mine from pepboys...55 american dollars)
2.) Crawl underneath the jeep and check your slave for fluid weeping OR leaks...this is not the cause of the fluid on your firewall but if you see that it is leaking and you only replace the master it will only be a matter of time and the new master will destroy the weakened slave. the slave is on the driver's side of your transmission housing with the hydraulic line that will lead back up to your master.
3.) replace the master cylinder (pm me if you need more details on this)
4.) as for bleeding, there is an allen screw near the master cylinder. it will probably be rusted beyond hell's gates. try it if you want, or take my approach...
My approach...bleed through pumping. keep the reservoir full and pump the hell out of the clutch pedal. you will be doing this for a long, long time but it's much better than the frustration of stripping out that hex key...you will literally be doing this for an hour. take breaks and all. you will get decent pedal feel just sitting stationary.
then take it for a gentle drive over uneven roads and turns. this helped me coax the bubbles out of the system. it may take a day or two to get full pedal feel back, but this DOES work on a 1995 ax-5 equipped YJ. debated this long and hard with my friends but when I had a working clutch pedal and they had a stripped allen screw, it was me that was laughing.
PS- do NOT fark yourself...KEEP THE RESERVOIR FULL! and you will be a happy man.