Is there an available substitute for the QSI Sidekick II controller that marketed in the past?

I have a Lionel V Transformer which has no integral horn, whistle and direction controller, the mentioned QSI Sidekick II I currently use with the Lionel LW Transformer, I am considering using the Lionel V for double mainline track. Also how can I electronically control the output of these two transformers to a maximum  16 to 18 maximum volts, by default I use AC panel mounted voltmeters and ammeters. TVS diodes will be attached to the transformer screwed voltage and common posts.