First of all you wont get a manufacturers figure, and there are lots of variables like jet pipes etc.

What I have done is to do more comparing than look for actual thrust figures, although would relate to some extent to installed static thrust.
Simply to tie the model to firm post on a flat surface, I use my hanger floor and a RSJ upright ! Fitted on the rope is a spring balance or the digital version scales, then just open it up and read the scale.

Some of the digital ones will record a max, some are a pain as they need a stable pull/weight to lock on, the old mechanical spring balance is hard to beat and accurate. You want it turned sideways so you dont have to be in the blast to read it.

We used to do this a lot in the ducted fan days when messing with tuned pipes etc.