You could do a lot worse than the 416 Taylor, a very fine cartridge that was once in the running for a factory standard, alas not to be and that is to bad. Personaly I would not, unless of course you want to, bother with 400 gr. bullets as I feel the 416 Taylor shines with bullets in the 300-50gr range. Although you can't go wrong with Hornady's 400 gr R.N. & Speer's 350 gr. mag tip is also a good choice.
As far as loading data is concerned, I would suggest getting a hold of one of Ken Waters Pet Loads articles, It was published in Handloader July,1974. While he uses the only bullets available at the time, Colorado custom bullets you should be able to get a starting point. He works up loads in a "Factory" chambered Ruger M-77 no less. Seems they made a couple back then, sweeeet. You can also get some info from, Nick Harvey's Practical Reloading Manual 1st edition, 1993. He has data for 300 and 400 gr. bullets as well. I use a 360 gr. LCFN mold from LBT for my cast bullet shooting in a 416 rigby with excellent results, I see no reason the Taylor wouldn't shoot them either. If you intend to shoot a lot of cast however, you might want to see about getting your chamber throat cut for them as it will also shoot the jacketed too. Throw a question out to Veral Smith on that one, as He is the man to ask that question to. Good luck on the project.
CRASH87