You will get problems if you have not "gauged" the timber fairly accurately.
That means shooting, straightening and edging the boards first, then run through the dim saw to the same width,
allowing a couple of mm each edge, to be planed off.
This will lessen the tipping experienced with boards of slightly different widths,
Which is the first problem.
Do not start G clamping, this how serious accidents happen! Metal on metal and all that
This tipping seems to be more of a problem with various thicknessers, particularly ones with rollers set in the bed.
I have had several "batches" tip and needing replacement while going through the Wadkin, Sagar, etc, in the past.
The technique seemed to be to edge plane with enough boards to be a "square" section,
So, edge planing 4" x 1" boards, feed 4 in together, 6" boards, feed 6 in at the same time with a man at each end keeping the 4 boards tight together
On u tube several edge planing examples can be seen but not with roller's set in the bed, it seems.
The only real and safe less wasteful answer is to get a jointer that compliments the lunch box type of planer, 'cos that's what it's for.
Face up and edge, cut to width on the dimension saw, and shoot the last edge, as we all know, is how it should be done!
Regards Rodders