Yes, slelenium toning has been suggested for b&w slides in the past. It should work fine for alt process negs.

If you want more contrast, why not just develop longer, or in a stronger developer concentration. Trial and error can be under safe light, then do time and temp once you are dialled in.

Then when it is time to print albumen, dont feel tied to the enlarger as a light source, A bare 40 w incandesant bulb can be a light source for contact speed print processes, and I suspect your albumin coating may be just that.