AS for being a good shot , only at the type writer. I wish I was a good shot. You could fire a 458 win in a Lott chamber and it wouldnt stretch enough to hit the end of a Lott chamber which is 0.300 -0.0350" longer. The brass would work harden or just plain wear out long before that happened. AS the case stretched slightly ,you would have to move the bullet seating die (with crimp) out a bit ,but cases dont stretch all that much. If you are just starting out ,a 458 Win has plenty of power for grins and fun, plus brass and guns are common. If you wanted a 458 Lott ,it would be better to just get the proper length cases .
My Lott has a 2.5X leupold and has had some lead shot added to the foreend to increase weight and balance a bit further forward.