A wet test would be best, of course, but if you are open to setting a weight belt on your lap to enjoy the jets, you might be alright. Some of our customers have tried various tubs in which they floated, and the thought of weighing themselves down to stay put just never seemed like a good idea - they did not get to enjoy the tub they really wanted. Others have given it a go, and were rewarded by having many other models open up to them.
Give it some thought -
Also you asked about the hard-wired 30 amp on the SX. Be aware that this tub has a 1000 watt heater. It's obviously not a huge tub, and 1000 watts gets and keeps it hot. But if you go 30 amp 110 you
still have 1000 watts: but you can then run both heat and jets concurrently. The tub can convert to 220 Volt 50 Amp, and that is when the heater jumps to 4000 watts. The difference between the cost of installation of hardwiring at 30A 110V and 50A 220V may not be much, and the extra heating capacity is worth every penny in my opinion.