Hi SFsecurity,
Twinvest is described in the book, while Synchrovest is described in another, earlier book. Lost cowboy has a Synchrovest spreadsheet.
The results of Synchrovest can be really spectular as shown by Lostcowboy using the 30% increase for selling.
With both systems you invest at regular intervals, for example monthly. Synchrovest also sells, while twinvest only accumulates.
When your twinvest machine is large enough you can switch to AIM.
Synchrovest can run indefinitely.
I use Twinvest now for accumulation while also AIMing the same ETF.
AIM sells can then be used to buy shares for Twinvest, so you don't have transaction costs. When the two machines are large enough they could be combined into one AIM machine. I will see how it all will happen in the future, not sure at this moment.
Best,K
