Had to look that up, I've used about every flavor of Hollowgram through the years and did not know what a Cannondale 1 was. I don't see it listed on their web site but the picture on the bike looks like an "Si". Which is the solid arm version of a Hollowgram (SL, SiSL2). It's a decent crank and is compatible with everything else (same BB & spider). The Si is the crank listed for the 2019 SuperSix 105.
All you would need is the tool for the ring on the back side of the spider. You can get Praxis chainrings directly from P2Max for $100 along with the meter (vs $150 direct from Praxis) a good deal and a decent chainring set.