mortac8,
It seems to me you are using small pads (not that it has anything to do with leg position). Would you be able to test a set of 4 larger pads and report the difference? Granted you’ll need a higher current intensity level, to generate the same contraction force: the current gets dispersed over a larger area. But you should be able to go higher if you have a decent machine.
In addition your stimulation will be more comfortable, because the nerves that pick up discomfort, are more superficial than motorneurons. Therefore current dispersed over a larger area will be more gentle on you. Overall you should be able to get a better stimulation: either stronger, or more comfortable or both.