I am not really qualified to offer advice as a low hours single spamcan pilot but I guess I can make a reasoned comment ref the rejected take-off.
I was always taught to keep a hand on the throttle during climb out to prevent it backing off uncommanded.
Having no lever would have presented this possibility and I suppose assymetric thrust at low alt could be a major problem,so maybe keeping it on the ground was the best option.
Comments that the OP was starting this thread as a 'shop window' for his personal flying skills add nothing to this debate.
Let's hear more about peoples' (successful) handling of difficult situations.You generally only read about the unsuccessful ones on the AAIB/NTSB sites.
MM