Re your second paragraph, don’t assume that your L:R balance will be consistent. I have the 2-sided Vectors and find that in normal rides the balance is anywhere between 45:55 and 51:49 (have had a few outliers but I’d say ~95% of rides are in that range). There are some trends - tends to be a more even balance at higher intensities, tends to be more right-dominant when I’m particularly tired - but nothing consistent enough that I’d feel confident enough predicting it.
For me, that inconsistency in L:R balance would lead to variations of >10% between a 1-sided and 2-sided (or hub-based) PM which is big enough that in my view it would render a 1-sided PM useless (or worse than useless if you paced yourself off under-estimated power and blew up as a result). Suggest doing quite extensive comparisons between your 2 PMs under different conditions, intensities, etc. Hopefully you’ll find you have a much more consistent L:R balance than me! If not then I strongly suggest buying the right hand Vector to upgrade to a 2-sided system.