Welcome to the wonderful world of cast bullets. You will feel very satisfied shooting your own home grown projectiles. It takes a special attitude or trait to cast bullets. After a few sessions, you'll know if you're cut out for it. If you are, you're in for a treat ! There's nothing magical or mystical to casting good bullets. It just takes time, coupled with a little experience, to get the results you want. After awhile, you'll be cranking out 500 bullets, in a little over an hour, with a 4 cavity mold. I've been casting for a little over 10 years and have never regretted starting. I actually enjoy casting as much as re-loading, shooting, and hunting. Plus, what else can you do on cold, stormy winter nights when it's impossible to do one of the above mentioned activities. During the winter months, I cast almost my whole years supply of projectiles.
Now to the meat of your questions. I would definitely go with the bottom pour pot. I use a RCBS, however, I'm sure the Lyman is comparable. Bottom pours are extremely fast compared to the dipper method. With practice, you'll get the consistant results you're after.(we're talking 1 to 2 sessions here).
As to molds, Saeco makes a .358 180 gr FN with or w/o gas check. They drop from my mold at .3595 when cast from WW and weigh in at 185 gr. Lyman makes a .452 300 gr WFN w/ GC, that should serve any purpose you have.
Just look in the links section on this site under re-loading supplies. Graf and sons and Midway carry Redding/Saeco products. Mid-south has the best prices for Lyman products.
Again, welcome to the exciting world of casting, where you are holding all the cards in your own hand, to decide what YOU want to send down your barrel. Any questions you have will be quickly answered on this site by many capable and able individuals with many different solutions to any problem. So jump in there, and start casting away.
I highly reccomend Marshall's Tech Guide and a book by Veral Smith called,"Jacketed Performance With Cast Bullets". This book can be ordered by going to Sixgunner.com and looking at their site.
Just about any question you come up with can be answered by these two books, along with a ton of information on why and how anything pertaining to cast bullets happens or works.
Hope I helped out and didn't bore you to tears.