I splice all my own gear from double braid, i.e tachyon, blue moon, poison ivy, blaze, velocity, vortex. --I started learning/practicing with used rope. BIG MISTAKE! lol almost discouraged me from ever learning. I buy rope by the foot from treestuff.com.
I'd start with a fid that is the exact size for the rope you are splicing so that your fid measurements will be right on. I've found Velocity was pretty easy to splice but others have had problems with it. Poison Ivy/Blue Moon is easy to splice with practice as well, but not what I'd recommend learning on because the rope is an odd diameter (11.7mm) so some of your measurements/fid marks may not line up just right which could be a problem for someone starting out.
Make sure that you pull the rope as much as possible before you start milking the cover over it so that it doesn't bunch up on you -- that can be very frustrating.
It would be beneficial to get your splices break tested and/or evaluated by a certified splicer before you climb on them.
my first splice took me like 2.5 - 3 hours, but I can do them now in like 10 minutes. practice practice practice. all the hard work pays off when you can replace your flip line for $15 instead of $80. or build a pulley saver for $60 instead of buying one for $200. I can make ring friction savers for like $12 my cost now. I made a custom extension for my rope bridge very similar to Rich Hattias Anchor Bridge system, but mine only cost me like $8. Its definitely worth learning if you are going to continue climbing. I still buy my climb lines with factory splices though because its only $25 extra.
Just think long and hard before you start climbing on your splices, know what you are doing and what to look for, just like inspecting your gear before you climb, and I wouldn't recommend running out and offering to splice up a bunch of new gear for your buddies either -- thats a lot of liability to assume, and it would be a tough situation dealing with a buddy's wife suing you for wrongful death, negligence etc if one of your splices from your new skill fails.
good luck and dont be discouraged by the 2 hours it takes to do the first ones hahahaha