We focus on the non-conflicting design of a multistage feedforward network with optical bufferless Switch and fiber Delay Lines (SDL) to emulate an N-to-1 output buffered multiplexer supporting variable length bursts. Y. T. Chen et al. [3] presented a sufficient condition (a bound) to guarantee the non-conflicting and FIFO properties in such a design. In this paper, we first point out the upper bound in [3] can not rise infinitely with the increase of the maximum burst length. Then, we develop a framework to construct a case which can be used to achieve a lower bound. Through simulation and performance comparison, we find the new bounds can significantly decrease the hardware cost for constructing such a feedforward SDL multiplexer while still providing the same performance guarantee as that of the old one.