The non-adjustable hooks is a non-ideal scenario. By far your best option is to get your own home gym set up or find another gym that has racks. Gyms that don't have adjustable racks are not serious about training. In the meantime you will need to find a comfortable position where you can clear the hooks. This will likely mean using a lower hook than you prefer. If other people are training in your gym you can ask them to help with the hand off and re-rack.