I've found that leaving the bullet large is almost always best. Don't worry about jump to rifling so much as getting the bullet centered and held on center until it is burried in the rifling.
This is how I try to set up bullets for throating like yours, which is most the most common throating with all bottle neck rifle calibers, as follows. --- I cut the body large at the rear and long enough to fill the cartridge neck plus most of whatever throat length will contain that diameter. The body area ahead of this portion I hold close as I can to groove diameter, with as much as .0005 undersize very acceptable with normal rifling, and slightly oversize fine also. This type bullet can be seated to touch the rifling without hanging up or debulleting ammo after being chambered. I never seat bullets so they jamb hard into the throat or rifling. A little jump doesn't hurt performance at all if the bullet has a strong drive band up front, but it can be destructive to accuracy, especially with stout loads, if the nose area is cut up with lube grooves.
