Track width for 2 stroke chassis with Briggs LO206

Need advice. Running a 2 stroke BIREL chassis with a Briggs LO206 chassis. Removed third bearing. Trying to get some advice on what track width should be.

I heard one guy say narrow the rear and widen the front but didn’t seem right to me. If it is right can someone explain to me why and where a good starting point would be for front and rear.

Most tell me to go wide rear and narrow front.

What model of Birel do you have?