Hello,
Unfortunately, there is no option in WooCommerce to show price if all the variations are not chosen but you may pre-select some most popular size in product settings http://prntscr.com/n48pfb and it will be active when you visit the product then the user will need to choose just metal to get the price.
Also, you have a lot of variations and I would suggest you to make 2px border to highlight the chosen variation http://prntscr.com/n48sse
.st-swatch-preview li.selected, .st-swatch-preview li:hover {
border-width: 2px;
}
And maybe highlight the variation price
.product-content .woocommerce-variation-price .price {
font-size: 2rem;
}
But it’s just suggestion.
Regards