Actually I have done a fair bit of shooting with a 250 grain cat bullet from my 357 Maximum. I'm only pushing it at 1300 fps or so, but I have no stabilization problems what ever. I cannot help but think that with jacketed bullets, the 1:18 will do just fine as they are typically shorter for weight than is a cast bullet of the same weight. 180's, 200's and 220's shoot just fine as well. 280's or heavier would likely give trouble.
I am pretty seriously thinking of the 357 Herret myself. The one advantage it has over the Maximum, is that it will give you a completely new throat. I'm not convinced that the Maximum reamer cleans up all the old throat of the factory butcher job. I suspect more and more that mine is still oversize in diameter, it is going to take getting some cerrosafe to tell the tale.
These three cartridges are essentially ballistic twins, operating at different pressure levels for each case. The advantage of the 35 Herret over the 35 Remington is that being based on the 30-30, there is no extractor work to be done. The 35 Rem is an odd ball case, nothing else is the same, and being rimless it would require special fitting of an extractor.
I think the 35 Herret is an exellent choice, but it can only be used with 35 Herret ammo. The nice thing about the 357 Max is that 38 Special and 357 Magnum can still be used in the chamber.