Why are those the only choices? Let the front L, C, and R speakers' internal crossover manage bass to their internal subs. Don't introduce another low frequency crossover into the L, C, and R signal paths by setting them to Small. Don't steal low bass away from the L, C, and R internal subs to send to the SVS. Set the AVR bass management for L, C, and R to Large. Let the SVS provide LFE and let the AVR crossover and SVS provide bass management only for surrounds by setting surrounds to Small.
When I use my surrounds, I think they sound better, warmer, when set to Large, and there doesn't seem to be enough low bass in the surround channels to send to the sub. If the crossover is above 80Hz, I hear the low bass fundamentals from the direction to my sub in the corner rather than from the direction of the main speakers. Low E string on a bass guitar fundamental frequency is around 41Hz. Low E string on a guitar is one octave higher, fundamental frequency about 82Hz.
