During a competition, and especially on a hot day, the heavy barrel is likely to deliver more consistent accuracy but another factor to consider is that the extra weight will help to stabilise the rifle whilst you are holding it for your shot.
Individual accuracy must be confirmed by shooting. Having said that, a lighter rifle may prevail in a 4P (20 shot total) match, with the situation possibly reversing when the competition changes to a 40 shot match with similar time allowance per shot. I say again ... Individual accuracy must be confirmed by shooting.
By the way, when you conduct your testing you may want to follow some recent advice from David Tubb. He indicated that changing powder and or bullet jacket material during a shooting session (without thorough barrel cleaning prior to the change) can have unexpected accuracy outcomes, i.e. use one type of powder and one type/brand of bullet for working up your long range loads.
Best of luck, and remember that there are two good reasons for dry firing before live firing:
1. To eliminate the creaks and smooth out the functions of your own muscles and tendons.
2. To smooth out the working of your firearm with especial reference to the trigger mechanism. The trigger needs a bit of working if it hasn't been used for a while and the more complicated triggers seem to need more working than the simpler ones after a period of rest.