Modification of K-member idler arm mount advice

I'm starting to think that this might be the case, I cant see what else it could be.

Since I'm really under time pressure to get the car on four wheels and away to get the chassis straightened I'm thinking about doing the following:

Installing the centrelink to give me the height of the idler arm and then locating it further by measuring out a rectangle like in the photo below. Ill have to check when I'm in the garage but I assume the idler and pitman arm are the same length and their geometry makes a rectangle like in the sketch below.

View attachment 1716119564
Makes sense to me.