What's a safe withdrawal rate?

I was recently asked my opinion on what a safe withdrawal rate for a deferred-tax pension plan managed with the Trend Asset Allocation Model. 

As a reminder, the Trend Model has shown equity-like returns with balanced fund-like risk. The latest update of the model shows another strong month, with a one-month return of 2.5% compared to 1.7% for the 60/40 benchmark and a YTD return of 18.0% compared to a 60/40 return of 12.8% (full details here). Model returns are based on out-of-sample signals, though based on a hypothetical asset mix.

The full post can be found here.