Down to 2 cams

My 2 cents is that the 901 spring isn't gonna cut it for a XE275HL. It has around 100 # of seat pressure at 1.65 nominal installed height, and at 1.15 open (.500 lift) it will have around 275 #. Turn the RPM up and you'll have valve bounce and maybe lifter toss. If you want to run a single spring look into the 926 instead. I would run the XE268 anyway, IMO its a better fit to what you're doing.