I got my Beta last week and I'm very happy with it but like many others, had a few minor issues. I've learned a little tweaking to items can improve how much I like them.
For anyone having problems with the support bar that holds the Alpha being loose when you slide it into the Beta, I found out scotch tape can help. Here's what you do:
Put the bar into the Beta and determine exactly where on the bar is covered by the hole entrance. Take a little scotch tape and wrap it 1 length around that part. It won't take much. Now you can put the the tape all the way on the end of the bar but it’s a tighter fit on the arm that's near the mouth of the hole. A little trial and error will get it perfect. Do this and slide the bar back into the Beta and you'll find it creates a tension that holds it in place and makes it nice and snug. I have not had any problems since. And because the arm itself is in the hole, its hidden and you can't see the scotch tape.
The other thing I did (temporarily) was to wrap a little plastic around the head of the Beta cockpit for when I have the Alpha and Beta connected in fighter mode. I took a litte bit of the plastic from the bag that held the manual and wrapped it around the cockpit head. I cut it and made a sheath out of it so I can slide it on and off. This way, when I dock the Alpha in fighter mode to the Beta, it doesn't scratch the yellow on the cockpit. The plastic is hidden since the cockpit is folded down between the Alpha's legs. Now its my intention to find a more permanent solution for that and find a way to cover up the yellow for when the Beta is in battloid mode but for the time being, it will due.