Hi All
I personally think, before we give this gent any advice, we have to consider a few facts here:
The main one being the model - She is a destroyer, not the most stable/suitable of vessels for a newcomer to the hobby. They do roll alarmingly and the vessel can be quite 'hairy' at the best of times until one has their confidence built up for sailing her.
I therefore suggest we apply 'keep-it-simple' Kis method - one speed controller wired up to the motors in parallel and then any discrepancy between the motors can be taken up with the facility of the trim on the rudder channel.
When one has mastered this and has become fully competent on the model and its behaviour one will then be able to progress to the next stage - i.e. two speed controllers (one per motor) on independent sticks - when happy can then move on to the third stage of adding a mixer which, by this time, full confidence in the model and of one's own capabilities can bring out the best in the model - and also make most of the amount of money that has been spent.
I am a little wary, as I have a Hi-Tech focus 6 radio. I had a lot of problems using this transmitter with the mixer. When I queried all the manufacturers involved in the electronics - came to the conclusion it was just me MY LUCK WITH RADIO GEAR.
One manufacturer did come up with something that seemed logical and that is that the majority of handsets are originally made for the aircraft industry. The handset I own may have the facility for mixing on board the transmitter itself. This may be interfering with the mixer I was using.
Anyway, hope this is of some help. Happy modelling.
Aye
JOHN E
BLUEBIRD