No reason to be nervous about using 2-Part, it's a tried and tested method these days. I got tired of mixing, so switched to a reactor, but it is very easy to dose and very hard to screw up unless you are pouring it into your tank. You can still precipitate a snowstorm with it though, so measure your levels everyday for the first week. The dosage amounts in the Holmes-Farley article in Table 1 ended up very close to what I needed. Use the calculator to find out your initial dose to get the CA/Alk levels where they need to be, then dose per the Table.
I've used Prestone Driveway Heat with no ill effects, but these days, with Bulk Reef as reasonable as they are, I'd just order from them and be done with it. Their large package will make enough to last you 6-8mos with 150gals for $63. But you could buy the same amount of A&H, Epsom Salts, and Mag Chloride for half that probably if you are comfortable with it. You can get 50lbs of the Driveway Heat with FS to an Ace for $24, that's hard to beat.