Hi F5Drive,
it doesn't make much sense to point the ip helper-address on your switches to a Virtual Server which is configured as DHCP relay. In the best case your setup would confuse your DHCP servers making them unable to identify the remote subnet and to provide a valid IP address from the the right IP scope. And in the worst case it would simply not work and making you angry...
Point the ip-helpers on your switches either directly to each of the individual DHCP servers (you can configure multiple ip-helper on a single VLAN interface) or use a single ip-helper and point them to a Virtual Server that is performing a regular UDP:67 load balancing for your DHCP servers (without SNAT applied). In this case the ip-helper will collect the 255.255.255.255:67 DHCP broadcast and transform it to DHCP unicast (src=IP-Helper:68 and DST=Virtual_Serer:67) so that it can be routed across your network environment and reach your Virtual Servers and finally the load balanced DHCP servers. Also keep in mind, that the clients must be able to directly access the individual DHCP servers for DHCP updates and DHCP Option 81 request, since they would unicast the DHCP server which had assigned their current IP address.
Note: A Virtual Server based DHCP relay configuration should use 255.255.255.255:67 as IP:Port combination. See https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/ltm-implementations-11-1-0/23.html for further information.
Cheers, Kai