VPN between Checkpoint and FortiGate works fine.
In the past when configuring VPN between Checkpoint and Juniper ScreenOS gateways, i just configured Phase 2 using Proxy-ID local net 0.0.0.0/0.0.0.0 remote net 0.0.0.0/0.0.0.0 on the ScreenOS site and set Tunnel management to "One VPN tunnel per Gateway pair" to let the Checkpoint use the same proxy-ID. This is not the best choice but it was the easiest and it worked. Same on FortiGate gateways.
and now to something completely different - CCVS, CCAS, CCTE, CCCS, CCSM elite