Consider having a small deployment of several ALS transport units for training. You can staff it as EMT/medic, and replace the EMT with a probationary medic to train them. Make the rest of the fleet BLS.
Consider staffing the chase cars with two medics. One medic can deploy to the BLS unit to make it ALS, and the chase car can still remain in service. If its a call where two medics ought to be working on the patient, then you already have two medics present, both of whom work together on a regular basis.
All-ALS systems aren't good for newer medics, IMO, since the general acuity of patents is low, which makes the learning curve quite flat (takes a long time to see a significant amount of seriously ill patients). Medics on all-ALS systems typically run mostly BLS and IV/monitor calls, and get to use their protocols very infrequently. In a tiered system, medics don't have to do sick jobs, postictal seizures, strokes (if they can protect their airway and are reasonably stable), drunks unless they're unconscious, injuries (if they need pain management, then call for ALS back) EDP's, or routine MVA's. That's probably 70% of your call volume right there. Medics can spend their time more productively on call types such as diff breathers, cardiac condition, cardiac arrest, unconscious, stat ep, hypotensive pts, and multi-traumas.