Yeah the setup you have at moment wont give you seameless roaming, basically the 2x 245s are working as independent devices. In this setup as the APs are not controlled in any way, therefore the roaming will be down to the device itself to decide.
Generally the device will hold onto the current AP until death; then it will disconnect and rescan for the SSID and move to the other AP. This is clearly not seamless!
To do it seamless you will need a controller in place to manage the APs, this can be either Software or Hardware. The Software version is FREE on the TP Link site if you have a spare PC to run this on (will need 24x7), or buy yourself an OC200 controller for around £50 / $US70
The OC200 is a small controller you attach to the same network as the APs, it will see the APs and allow you adopt them into management. Once managed in settings enable the screenshot below, this will turn on seamless roaming.
Now they are managed the OC200 will do the work for you and it should be seamless provided the device supports this (most now do in practice)
Fast Roaming.. its fast roaming (seamless as you say) and its offical standard is 802.11 K V R
Dual Band allow it to roam from 5Ghz to 2.4Ghz and back.. etc etc.. if this is off it will only move 5 to 5 or 2.4 to 2.4
Force Disconnect.. if the device doesnt support 802.11KVR (roaming standards) it will force the device to reconnect if its closer (stronger / better signal) on another AP.. basically forced roaming for old devices.
My recommendation.. buy an OC200 as its cheap and works (have one myself for my 3x 245s). But you will need to cable the 2x networks / switches together in some way, without that central management they will continue to work as individual APs
Hope that helps!