1993 Mercer Vinyl Single Hung Balances

Hi Swisco!
I am having trouble identifying the correct shoes and length of balance to order.

I need 4 balances that will fit this window. The only thing that is left to identify them is the broken plastic shown here.

The entire sash height is 29 1/2" and I am unsure if the balance would be a 27 or a 28 for this sash.

There is a lot of room between the frame and the sash sides that makes me think the deeper bottom shoe(1 3/32") will take up some of the "slop" as opposed to the narrower bottom shoe.

I don't have any more information because I foolishly didn't remove the one working sash to look at the balance markings when I was at the inspection.

Its a rental and I would rather not make a second trip to bother the tenants to take a sash out--but I will if it is the only way to identify the correct balance.

Thanks!