My 2 cents:
-If you are just doing shallow rec dives well within your training level, know your SAC rate, have reliable buddy, then you are managing the most important factors, IMO
-But redundancy is basic to risk management, and if you are deviating from the above, its even more important
-my personal experience is that wireless gas transmitter failure rate is comparable to hose tethered SPG issues. (Just my personal observation, totally unscientific)
-I have Petrel 2 and think its a great product. I would expect Perdix to be as good or better, and I would buy the AI model to maintain future flexibility.
-If you do buy the transmitter, having gas data in the same place on your wrist as other data is very convenient. If you are doing non-deco, single gas dives, the screen is not too busy
-Why not rent or borrow any gas integrated DC first just to see if you like that config?