Daks-
Try Midsouth Shooters Supply for that kit. They have it on sale for $219.99, and shipping might be less, too. The item # is 044-9357.
www.midsouthshooters.comIt comes with the Speer reloading manual, which is a good one. I'd also recommend the Lyman #48 manual. Read the how-to sections
completely, not just the load info.
Yep, you should have a good set of stainless steel calipers. You shouldn't need small base dies for the pump, which is good, because they can be hard to find in .35 Whelen.
As for pressures, that will be explained in your loading manuals. Suffice to say, the reliable methods for measuring pressure are not often used by Joe Average Handloader. You need a pressure gun, or an Oehler Research PBL to really measure pressure. So, yeah, you rely on the manuals to give you a safe range of loads, but you never trust them completely. Start well below the maximum charge, and gradually work your way up, keeping a sharp eye for any signs of high pressure. If your load is giving sticky extraction or some other pressure sign before you reach the published maximum,
stop, and reduce the load by a grain or so! You're at the maximum for your gun.
Whole books have been written about all the nuances of reloading, and your best bet is to start reading them. Your local library should have the
ABCs of Reloading books, read the most recent one available. Get multiple sources of load info, just to be sure your powder amounts are correct (yeah, they publish mistakes in those books sometimes, so always double or triple reference your loads). Besides buying lots of loading manuals, most of the powder companies will send you a free loading manual.
In the same vein, never trust reloading data that you read on the internet, unless you can confirm its safety in your own published load manuals. This is especially important for someone that's just starting out reloading. You just don't know if the information you're getting is coming out of left field, not until you stick a bullet in your barrel or rupture a case.
Reloading is completely safe, if you do your homework first, and use some common sense. Have fun, be safe.