Inasmuch asI use only rear carb engines - I do all my new model designs --and redo setups on existing kits as follows:
The engine mount -be it a box or whatever-- is triangulated such that the top of the box can still be open-and still be rigid.
This allows simple routing of throttle linkage - etc..
It really is not rocket science-
Once you digest a rear carb setup , you will likely prefer it -
I now run most choke linkages out a top corner of the cowl- which makes starting very easy - the ignition switch and a little pull wire -are close to each other.