I would definitely suggest the bonding bath. It sounds mean, but putting them both through a new and scary experience can often make them rely on each other for ccomfort. The bath is beneficial because they will come out smelling the same which adds to the 'your in my group' feeling. A good company for shampoo is gorgeous guineas. Their stuff doesnt contain parabens and sodium laureth sulphate which - tbh- ticks my boxes. I've hear johnsons baby is pretty useful too. I used it in my early days with no ill effect. Just make sure any shampoo you do use it completely washed out!
I wash my pigs in the bathroom sink. I add nice warm water (test with your elbow) up to the level that woudl reach their chest. Pigs will do an 'n' shape when they hit the water so you can afford to put more than you think in. You can always pull the plug for a second or two until you have the right level

I support the pigs front legs with my left hand (which stops them scrambling too) and soak the pig from the back of the wars down and lightly on the chest. Leave the head alone, they clean that bit themselves with the eye milk they make. Add a strip of soap down the spine and massage in well.. Dont forget between the legs, the grease gland at the furthest part of the back (before you hit piggy buttocks) and the tummy.
If you have a sink which has one tap so you can control the water temperature lucky you! You can rinse piggy by swooshing them systematicaly under the tap (avoiding the head!). If like me you don't, it is a good idea to have a bucket and jug of pre-made perfect temperature water. Pull the plug on the soapy water and once its drained rinse off your pig in the sink using water from said bucket! Wrap your pig in your most absorbent luxurious towels and give a thorough (but not too rough as the greasegland and neck fur is sensitive) hand dry. I then use my hair drier on the least hot setting and get my partner to hold the piggy with tummy showing.. Dry this bit first because when piggy is put down it will be covered up the whole time. Then turn them over and lift up the hair on the back and sides getting to the base. Pigs can take a while to dry. I often keep them out for an hour on towels and encourage active play. The raised body temperature will help them dry. It normally takes an hour or two before I am happy that they are dry enough to go back.
The first few times you do this will seem to take an age as you get used to it. But I've done them enough in the past to manage a wash in 5 minutes and let them play on my bed with plenty of blankets for 1.30 hrs, whilst I mess on my pc or watch dvds with my bf.
Good luck, I hope this little nugget is useful! It's helped me with a male/female bond that was patchy, never fought again. But boys can be different. You've done a great job increasing space first! That is the most critical thing. If you dont see things get any better you may be able to resort to keeping them seperated in the cage with a divider but they can still see and smell each other and have conversation. They can also spend outdoor time together if you can trust them to be more interested in exploration!