That set of ailerons should roll the sucker at least one revolution a second. There are a number of Extras that have the same size ailerons and they roll decent, if not blinding fast. Those will do the job if they're deflected enough.

It doesn't matter much what the specs are for the model servo you're using. If the two of yours that are in that airplane aren't doing it, they aren't doing it.

It doesn't matter what your computer radio says for throw. 140% throw reported by your computer radio isn't always 140% deflection of the ailerons. Matter of fact, change from 100% in the radio to 140% in the radio, and most times, the change in deflection is a lot less than 40% more. So set your radio for 100%, and RIG THE CONNECTING RODS to give you at least the deflection called for in the manual. And if that deflection doesn't give you the roll rate you want, then change the RIGGING OF THE CONNECTING RODS to give you more.

And if that last change doesn't show results, your servos aren't powerful enough to get that deflection in the air, under load. So either your battery is dropping out on you, or the servos are failing, or the pushrods are flexing.

There are any number of reasons the airplane isn't rolling as fast as anyone would expect that design to roll. It'll be up to you to figure out which reasons are the problem. And you've gotten a bunch of good suggestions to look at.

BTW, got a picture of YOUR airplane? That shows the aileron gap? Aileron gap has got to be horrible to have that much effect on roll rate.