That is literally the lowest dose you can take and if you have a tolerance to the hydrocodone then the risk is minimal but every person is different so as others said be careful.
A lot of people enjoy what is called "the nod" but for me this is a HUGE red flag because if you take these drugs and have a strong desire to pass out, you're on the edge of ODing. This combo may make you want to sleep even though you may not have taken to much because of the valium so you definitely need to be careful. If you obtaining these from a pharmacy and are sure of their ingredients, you should be able to find a dose that works for you and as long as you stick to it or don't go crazy on the dose increase, you should be safe but nothing is certain so always be safe and try to use with someone that can help you if things go wrong.