The fusible links supply things like central locking electronics, alarm system, clock and so forth. This is known as 'parasitic draw', and should not be an issue on healthy batteries. The classic I see is the youngster with the big amp in the boot for his stereo, 'his mate' told him not to power the amp switch on from the ignition, 'better to be powered up ready for all the sounds dude!' Never heard a Spaniard talk like that but it runs through my mind as the owner is still scratching his head. Of course it sucks the life out of the battery.
So back to your car, Paul is right, the area between the rear of the alternator is not particularly spacious, there are already issues with the oval plug wiring giving issues on 80's. I would not compound that by having the extra wires there. As you are in 'wiring mode' then either renew the fusible links or swap them for fuses and if you do not want them on the battery then get a 'bus bar' post and fit them to that. The FL's are becoming a regular failure area in the 80's due to age and corrosion, open the little box the actual links are in and check it for corrosion.
I am guessing you have run the main charging cable to the starter battery on the passenger side? I too did this a few years back when doing my 12v conversion, it seemed right at the time but experience IMO dictates it is the wrong thing to do assuming you have a VSR?
My original thinking was to prioritise the charging to the starter battery, and yes it worked fine but certain things were on my mind and reminding me as to why it was not such a good idea.
The first problem is starting up, you take some juice from the PS battery, the alternator will spend some seconds (or longer) to bring that battery voltage up to force the VSR to 'bring in' the DS battery, all this is fine but, if it at night you will find that depending on the starter battery voltage and the VSR's timer, it means everything on the DS battery has only what is left in after you have had the fridge on or some other power drain, in other words you have no or very poor lights, the dashboard gauges will not work properly, these get power from the FL's mentioned earlier. To be fair this is not a major headache, perhaps a minutes delay and your starting to get juice again from the alternator, and everything perks up and all is good but worthy of note.
The other thought that occurred to me is alternator failure, whilst very rare, sometimes the failure mode is not always 'no charge', the other trick they perform is for a diode to fail and then suck the life out of your starter battery. Having a VSR is good, if this was the OE 24v install you would now have two flat batteries and not just the one. If you have a decent VSR you can force it to jump start to the starter battery using the DS, I am sure you know this anyway, but you can then disconnect the VSR and retain engine running and electrics from the power in the DS battery, keep non essential electrical items off, and drive a long way to a garage or even home, this is why I kept the starter battery completely isolated from any parasitic drain including the alternator.
There is a third item but it is only an issue if the cables between the VSR and the two batteries is not heavy enough to ensure no resistance, I am not talking about carrying over the amperage for starting, but the actual resistance to voltage drop, if there is resistance then the DS battery (with all the vehicle electrics) will not see the full voltage from the alternator (battery sensed), so will take longer to recharge, and other items (lights for example) will not be as bright as they could be, a niggle really and sorted by using a heavy enough cable if you haven't already.
regards
Dave