Unfortunately, there really isn't a best time to get there to minimize the wait. Expect a wait time of up to 1.5-2 hours to get seated.
There are two lines, one of which is for the higher level gaming card members. However, their line system is very disorganized as they merge right before seating takes place. One of the key problems with the Studio B buffet is that you are required to pay for your buffet WELL before you are seated.
The wait times DO vary dramatically, depending upon any local's only promotional activity that is underway. So, get there as early as you can. On weekends, the buffet stops taking in customers at 10 pm. However, they essentially stop refilling food trays at 9:30 pm. or so and start removing the trays completely about 10:15 pm.
If you get into line any later than 8 pm for the weekend seafood buffet, you might not get in, or will simply be eating scraps. At the weekend buffet full assumed cost, it just isn't worth it to eat there after 8 pm; the food isn't THAT much better than other buffets.
For example, We tried to eat at the M buffet last week. On our first day, we got into line at 7 pm. We paid for our meal at the cashier around 8:20 and were not offered offered seats until exactly 8:50 pm. By that time, they had stopped refilling the food trays for a while and about 1/3 of the food stations items were completely empty. After waiting for about 2 hours, having paid but not getting seated, we spoke to the line manager and got our meal cost refunded. She told us that a local coupon was being used that ended that day, and that we could return tomorrow and completely avoid any line.
We returned the next day, a full two hours earlier, with a black comp card to avoid the line. Wouldn't you know it; a new local coupon came into effect that day! Once again, we waited for more than an hour, even in the accelerated comp line. In truth, having gone in with very high expectations, based on a bunch of glowing reviews, the Studio B was one of the more disappointing meals of our entire trip to Henderson.
Studio B is not worth waiting in line for at any time...The foods not that great.