I have two 110Vac solenoids to drive a hydraulic guillotine up and down. My inputs are from 2 24vdc relays with the 110vac running across the n/o contacts with a snubber across the contacts.
First question is can I keep the solenoid that drives the guillotine to the up position on most of the time or will it over heat?
next question can I use one signal to the relays via an inverter so when one is off the other is on and use switches on the guillotine so when the down solenoid is activated ( the up solenoid will be off) the down soloenoid is on until the guillotine hits the switch at the bottom , the switch then switches the down sol off and the up sol on? is that practical?

 

We can't tell from here whether your solenoids are rated for continuous duty. Plug one in and watch it for a while.

The rest of this is just wiring.

 

This is essentially just a latching relay circuit where the "set" input starts the process by powering the down actuator until the lower limit switch (reset) is operated.

Use a spare changeover contact on the relay to drive the up and down solenoid relays, thus preventing them both being active simultaneously.