30.5 arrow length would of given you perfect spine. Also the program said 58 gr was standard insert weight and being that it made 501gr arrow I went with it.
The biggest gain to be had is dropping down to 100 gr heads. If you added the bushing and heavier fletching and dropped down to 100 gr youd be right there at optimal. Any weight on the back would help though.
Id go with a .270 and a .375 HH mag if your planning on hunting moose anywhere there is grizzlys. A 270 or 30-06 will do it all but I sure like my 375. Really puts down the big critters quick.
I don't have any experience with those guys but if I don't like the shipping cost I just don't place the order to begin with... Looks to me like the OP just joined today to bash them haha