You should think about this first.
I was told that if you add memory to the SCSI kit board that you must then slow your RAM speed down by 10ns to 70ns. In your case it would be slowed down by 20ns.
Maybe I was told incorrectly. But it made sense when they told me that RAM on the Addon board is further away and the CPU can't drive it as fast.
When I say "slow down your RAM speed", I was told there is only one speed setting for the whole Blizzard 1260. So u would be throwing away ur expensive 50ns SIMM on the mainboard and the one on the addon board.
But don't worry, if u give me some time I will buy ur SIMM from u so it doesn't go to waste. As long as it works.