I went to Helios website - but it was under construction.
To answer your question - if your ballast enclosure has two separate switches - then you may be able to use two independent timers. One plug powers ballast components, two separate swithes control each light/lamp circuit - on/off.
So the system is designed to allow for only one, or both light circuits to be either on or off.
Both A & B off
A on - B off.
A off - B on
Both A & B on
Intermatic make some nice digital timers - that are intended for direct wiring to the circuit ( they don't have a typical plug like most other timers we use ). You can find them at Home Depot - I've seen them there.
This of course would require you opening the ballast enclosure, and wiring into where these two switches, providing you have the room to do so.
You could leave the swithes in the "on" position, and just wire to the timers. Or you could remove the switches - but no reason to really.
First I would contact Helios - and run it by them to be sure.
I would not suggest doing this yourself unless you've had some experience wiring up AC circuits.
An electrician could do this easily for you though.
Or ....... there are options now from PFO ballasts , where they use the same Intermatic integral timers mounted right into the ballasts. I'm using one of these dual timers ballasts to run my 400 watt VHO ( picture below )
Again - checking with Helios would be the best route in my opinion.