Congrats on the VLR’s a fantastic and as you have seem overlooked coax that can give the deservingly lauded Kef a run for the money !!!
on stands I would say concrete is pretty light, porous and resonant in blocks, invest in some Sound Anchor or other metal stands, Blu Tac is worth its weight in gold!!!
do not modify the inputs, even the 7 use the barrier strip gold plated soft brass tied directly to the crossover as only the frugal Dutchman can do
serious do not change those !!!!
enjoy and keep us filled in !!