I am growing a Lapins cherry tree in the bay area, zone 9B, sunset zone 14. I planted the tree last year in spring. It was about 8 feet tall and is now about 10-11 feet tall, it is quite vigorous. At the time it only had about 4 branches and I presume was already 2-3 years old. This spring before bud break I pruned back the lateral branches about halfway, and then it vigorously sprouted branches from those cuts, usually in 3 directions, as well as branches below and above those. For a sweet cherry such as this one, do you recommend central leader training or more oven open or vase style training? I have seen conflicting information online and was wondering if it is too late to top the tree at a relatively low height (i.e. right above last year's scaffold branches) to change its shape. I thought that sweet cherries should be trained with a central leader but now I have read different advice on the internet. The way branches are growing in every direction seems quite chaotic and I'm wondering if I missed my chance to give it a more rounded shape. Would I be able to prune it now during summer or should I wait again until next season? It is pretty much already at the height I want it to be but the canopy needs to fill in. The stem has thickened quite a bit. If I have to keep it as a central leader trained tree, then how many main (primary) branches should I keep? Also I've tried with no success last year to spread the branches to a more obtuse angle with metal branch spreaders and by tying them with string to stakes in the ground. It didn't matter, despite 2 months with those aids, the branches just bent back into an upwards shape.

Please let me know if you have any advice. Thanks!