I have got twins in reception who are at different levels for some things e.g one is four reading levels above the other and is much more advanced at numeracy. She has just picked things up quicker.
Different classes has worked extremely well. I am so glad we did that. Don't think of it as stretching one and not the other, stretch them both! By doing the appropriate things that will stretch them as individuals.
The less advanced twin has had her own moments of success, won an art competition, showed the head her work, brought class mascot home for good behaviour all of which were celebrated by us. We had a lovely moment when they were both class champions the same week as well.
We also praise effort a lot e.g dt1 "I am now on xxxx book level!" We say " it's great that you both love books and try hard at reading"
Luckily dt1 is modest but she is very competitive indeed. So in conclusion:
-different classes -stretch them both, give equal time and focus -celebrate all successes - praise effort
School have been fantastic and it hasn't been a problem
Just treat then as individuals. I'm not a twin expert, but a mum of 3. If dt1 is all about the physical, praise him up for that. Get him in a gym class or football or whatever. Find what he likes & let him know you're happy for him to have his own interests & strengths, seperate from his brothers. As long as you try & be involved in some of the things he's interested in & spend similar amounts of time with him as you do with his twin doing the academic things he enjoys, there shouldn't be any resentment. So if you spend half an hour with dt2 playing chess (or whatever,) then let dt1 knowhe will get half an hour later. It doesn't matter what you do together, as long as he doesn't feel sidelined. I've tried to do this with my, to praise them for whatever they are good at. Dt1 may not realise how wonderful he is at sharing or how creative his drawings are (or insert appropriate talent,) and think he brother is better than him because he's good at academics.