Probably hard to find one to borrow as I assume most are inline and in use.
Maybe just purchase an inexpensive Denon or in my case I got a Fidelity Research FRT3 for the work rig. IF you go used and decide to sell you won’t lose too much turning it over.
I got my FRT3 (adjustable high and low) for a couple hunski which should match your phono stage ok.
I wouldn’t worry about loading; maybe later if you decide to go the SUT route.
The GCPH is almost vintage so you might hear a difference.
I used my Hashimoto HM-7 with PS Audio's first phono stage (actually first product!) the PS-1 and it sounded pretty good!