BJ4 non-WE to BJ2 conversion - a few Qs

[colmo]

I'm planning on a BJ2 conversion using an original BJ4 chassis, GT2 front sub-chassis and B4 front end.

My original plan was to modify the chassis by simply extending the taper at the front, slicing off the extraneous bits, finishing in a point.
To this, I'd attach the GT2 piece.

However, this is going to result in a long wheelbase - about an inch more than a B4. Could this work? It appears to be well within the legal limit BRCA allow (460mm total length).

The original chassis can't be shortened much due to battery slots. I could cut a G10 chassis myself, or have a CF or alloy one cut.