last night me and a buddy was out with our H nitro's having fun on our oval we have set up. One thing i noticed that both boats, on occasion would spin out on the striaghts. Sorry for the word " spin " but i am a stock car junky and dont know the word for a boat getting its rear lose on the striaght and doing a 360 or close to it LOL. anyway. we were running our boats very close, and it was never the boat in the lead. Also never happened when running one boat by itself. the second boat seemed to be catching the wake of the other boat and comming down in the front, the front seemed to grab and the rear would kick sideways and spin around. maybe thats not exactly what was happening, it was starting to get dark. Could this be a trim tab issue? rudder issue? Wieght? what are my options please.

Sounds to me like the front end is stuffing. You might want to try and get it abit further out of the water, but not so far that it blows over. I will ask before the rest here do
What is the depth of your prop?
What angle is the prop at is neutral, negative or positive?
I woudl bet you need to put abit more prop in the water to try and get that nose up abit more. Sounds to me like it is catching the wake jus tliek you said, then it is stuffing. Also, try staying out of th eothers wake, that might help also