Yes, you can use per diem or actual just like always, as long as you meet the requirements for deduction in the first place:
To meet the directly-related test for entertainment expenses (including entertainment-related meals), you must show that:
The main purpose of the combined business and entertainment was the active conduct of business,
You did engage in business with the person during the entertainment period, and
You had more than a general expectation of getting income or some other specific business benefit at some future time.
Business is generally not considered to be the main purpose when business and entertainment are combined on hunting or fishing trips, or on yachts or other pleasure boats. Even if you show that business was the main purpose, you generally cannot deduct the expenses for the use of an entertainment facility. See under What Entertainment Expenses Are Not Deductible? later in this chapter.
"Generally, your tax home is the entire city or general area where your main place of business or work is located, regardless of where you maintain your family home. For example, you live with your family in Chicago but work in Milwaukee where you stay in a hotel and eat in restaurants. You return to Chicago every weekend. You may not deduct any of your travel, meals, or lodging in Milwaukee because that is your tax home. Your travel on weekends to your family home in Chicago is not for your work, so these expenses are also not deductible. If you regularly work in more than one place, your tax home is the general area where your main place of business or work is located. "
"Travel expenses paid or incurred in connection with a temporary work assignment away from home are deductible. However, travel expenses paid in connection with an indefinite work assignment are not deductible. Any work assignment in excess of one year is considered indefinite. Also, you may not deduct travel expenses at a work location if it is realistically expected that you will work there for more than one year, whether or not you actually work there that long. "