So I thought I'd repost this as my reply was buried in the midst of my last thread. This is more from my tube welding practise. Conscious that the outer weld should have been closer to where the two materials join but I'd welcome comment
Your first Weld looks fine the top weld in the second picture looks a bit big and maybe some practised on finishing the Weld. the bottom one is offline they also look a bit high you could probably do with a few more amps when Im welding the end of a box to the side of the aother I wouldn consider the side as the thicker material and start on that it will always take more heat than the end of the box