Media cat will tell you what you need to know. Look at the first four mumbers of, say the top cover 1128 xx xxxx is a 044,046,MS440/460, 1121 xx xxxx is the 026/MS260 family...
Red oak splits like a dream! Whittle it from the outside in using your tool of choice. Yes it is worth it and the crotches are the best burning wood in the whole tree.
For drills my vote goes to Panisonic!!! I have used all of them at one time or another and the Panisonic is by far the best I have ever used. $$$$ but worth it if you use it a lot.
I would braze it. If you have to weld it nickel rod with both pre and post heat will be the best. Also peen the weld after every inch or so of weld will help eleminate stress cracking. You also need to U-grove the crack as cast don't like sharp corners. I would braze it. Nickel rod is also $$$.
My medium wood is 20"- 36". What is yours? Some may say 24"-40" others will say 10"-20" "Medium" means different things to different people. 346xp small, 372xp medium, 395xp large or just get a 3120 and cut it all.