Commercial office sub lease question

[Aaron Anderson]

I have a commercial office space in Boulder Colorado 80302,  that I currently occupy and I want to lease it out on the days I am not using it. It's available five days per week. l have a real estate attorney on retainer to draw up a contract when I find a tenant to make sure I do not violate my current lease in any way. This lease will be up for renewal 9-1-22

Should I send the landlord the letter of intent to sublease before or after I learn what his new terms are for the new lease.

Are there any resources I can use to determine what the space should lease for? It is 750 Sq ft., fully furnished and ready to use.

Where would you suggest we advertise the space for lease? 

Should I rent it at a monthly rate or just by the number of days the new tenant wants to use it. They might only need it for two days a week. 

Thanks for your help!