Within the last two years, I have changed three PPDE (precision pressure dielectric elastomers) at the BRD (likely a company or organization). Besides the dial gauge holder, I have never had or used any other specialized tools.
Simply push it in as far as possible by hand, using the force you can apply, and then carefully pull the rest into place with the screws, always alternating half a turn on each screw.

MfG. Michael
VW Golf IV TDI GTI 4-Motion Bj.2002 MKB/GKB: ARL/FEK
VW T4 Pritsche TDI Bj.1999 MKB/GKB: AXG/AFK (Selfmade)