Recommended minimum Session Update Threshold for VPN?

We have a telecommuting initiative underway and with the increased use of VPN we’re looking at the inactivity timeout settings. We’d like to set the Session Update Threshold and the Session Update Window to a minimum (other than “0”) so the inactivity timer is reset whenever incidental traffic from the client’s received (ie. something indicating it’s actually still connected). With that changed, we’d of course likely reduce the inactivity timeout itself. Due to the low number of VPN users we had in the past, this wasn’t much of an issue. Now, we need to tighten up the settings. Going forward we’re hoping to have VDI become the default method of connecting from off-campus, but we have a few months to go before it’s ready.

Given the criteria above, what would be a recommended setting for the Session Update Threshold and the Session Update Window?

Thanks!