Window buck problem

I’m attaching a picture with two circled areas on them labeled 1 and 2. Basically we have placed bales below where the windows go and I thought I could just “float” the windows on top of a 2 x 4 or 2 x 6 on top of the bales and then install a box beam above for the upper framing of the window. Normal windows would have king studs with trimmers and jack studs beside them but I thought with these big posts on either sides of the windows I wouldn’t need them. But now after placing the bales I’m thinking that I don’t know if this is such a good idea.
In photo area 1 I was going to have plywood strips attached to each end  of a 2 x 4 sill plate which would be pushed down between the bale and the post and then screwed in to the post as a way to level and firmly attach the 2 x 4 sill plate on top of the bales.
In photo area 2 I was going to have a box beam attached by screws into the posts on either side (no jack or trimmer stud) so that it would only be held in place by the screws through the sides of the box beam into the posts.
Anyway - I am totally doubting this to be a good idea but I don’t want to take the bales out and frame it as in stick frame construction but I’m wondering if this is the only way to precede.
Thanks for any and all help.