I have to wait until Tuesday to get authorized in Bittrex. I had everything in Bitfinex but they're stopping their association with US investors. I've looked at a Trezor for offline storage.

p.s. I'd LOVE to see a copy of your spreadsheet. I've recreated what I saw you post, but it's the rebalancing part of it I get screwed up on. Would appreciate to see/use your version!