You don't need a trap gun to shoot doubles. Any good o/u will work if it fits you and it shoots where you look. I think most trap gun shoot too high for me to shoot doubles with. It would be great if you could try a few different guns before you buy one. Either of the brands you mention make good guns. Half the fun is looking for a new gun.
As mentioned above;make sure the gun shoots where you look or shoots for you. I purchased an MX 14-L combo for 7,500 dollars, but could not shoot doubles consistently with the O/U bbls. I went back to shooting my 750.00 dollar Charles Daly Venture grade to get my average back up to where it was prior to shooting the Perazzi.
Shoot as many different guns as you can before purchasing and don't worry about the make or what it looks like. Get confidence in the gun you settle on.
I Have a Guerini Impact that I bought mainly for sporting clays. I don't shoot doubles very often. This year at the MD State Shoot I had a good day Sat in the singles so I decided to come back Sun and give overall a try. I had not shot doubles in over a year and had never used the Impact for doubles, managed to shoot a 90 with it. With a little bit of practice mid to upper 90's should be easy.
I had a Joel Etchen 687 combo before and the Guerini O/U has an adjustable rib and a better trigger. The Impact makes for a nice sporting clays gun also.
I have shot both trap and sporting guns, in all the brands mentioned and I like an O/U set to shoot about 50/50 POI for double trap. Most people don,t shoot the first target fast enough, so the second target is dropping by the time you shoot. So tell me, why do you need a gun that shoots high? Again, everybody is different and the gun has to shoot where you are looking. That is why I like the guns with the adjustable combs and ribs so I can make my shoot where I want it to. Believe me I have been beat by guys with 870's. It is the Indian and not the bow. Buy the best gun you can afford, but I do like adjust-ability in target guns. Good luck.
Back "In the day" Britt Robinson shot singles and doubles with his MX-8 pigeon gun IM/F and Gene Sears shot doubles with his Browning Superposed M/F Lightning. Both were terrors at Doubles. IIRC Britt's MX-8 had 32" bbls and Sears 30"
For the little fooling around that I still do at Doubles my flat rib SC3 pigeon gun 30" Briley Chokes is what I use for everything now. I occasionally shoot over a skeet bird from low gun because my monte carlo stock is just a tad high where I see (barely) some rib. 60/40 bottom barrel and ~ 55/45 with top. I'm old and slow now but I still stay in the mid 20's at all the clay target games just by switching chokes.
My only point is that used perazzi's and older brownings didn't lose their ability to point and shoot. The advice to 'borrow' different friend's lower stocked O/U trap guns is good advice and would be a good place to start.
The adavantage of Guerini's trap O/U over Beretta and others is their adjustable rib which allows you to dial it in. Guerini's are a great value. Nothing wrong with Perazzi, Beretta, Brownings and the others, I own many of them, but dollar for dollar its hard to beat a Guerini, they offer more for less plain and simple.
Redcobra, I shoot doubles with a fixed Mod. and full. Also agree with dawg about the choke.The modified choke does not cost me first targets and yes, I believe that too open a choke will cost you targets.
Pete McCall from Kentucky often carried Doubles averages in the very high 90's. Didn't he shoot a Winchester SX-1 with one tight choked barrel? Anyone here ever think they were better regardless of choke used!!