To ease developers work in an industry where FPGA usage is constantly growing, we propose an alternative methodology for architecture design. Targeting FPGA boards, we aim at comparing implementations on multiple criteria. We implement it as a tool flow based on Chisel, taking advantage of high level functionalities to ease circuit design, evolution and reutilization, improving designers productivity. We target a Xilinx VC709 board and propose a case study on General Matrix Multiply implementation using this flow, which demonstrates its usability with performances comparable to the state of the art, as well as the genericity one can benefit from when designing an application-specific accelerator. We show that we were able to generate, simulate and synthesize 80 different architectures in less than 24 h, allowing different trade-offs to be quickly and easily studied, from the most performant to the less costly, to easily comply with integration constraints.