Of course you want an elite goalie, but you want them before they get the elite cap hit (just like you want your young guys contributing before they hit their 3rd contract).
Giguere at 13.64% of the cap at time of contract signing is the highest % goalie to win in the cap era. Vasilevsky winning his 2nd cup on 11.6% is the only other goalie above 10% of the cap at time to signing to win it. (he was just 4.79% for cup #1).
Quick (9.67% against us), Thomas (8.82), Crawford (2nd time 9.33%), Fluery (8.33%) and Holtby (8.54%) are the only other notable % numbers. Of those, only Crawford over Bishop and Holtby over Fluery (by 0.2%) had a higher cap % than the guy they beat.
8 of the 18 winning goalies have had a caphit of less than 5% of the total
On the other side of the ledger, 6 guys have had a % over 10 on the losing side, with another 2 above 8%.