i have to crawl in on all fours and handwater 6-7 litre at a time.... bit by bit, a litre at a time without it all pissing out the holes in the sides of my airpots. Takes ages and I hate it.... bud in my ears/eyes etc.
My nute mix swings from 5.4 to 6.5 over 24-36 hours..... I just adjust before each feed and go.
Coco will buffer the pH to some extent, so I wouldn't worry... a bit of swing in pH will make certain elements more readily uptakable. I think Coco sits in the low pH6 region so keeping the feed pH under 5.8 when feeding will keep the pH right in your medium.
If you're really worried, check the pH of the run off every now and then.
Have a look at Blumat Tropf watering system, no pumps etc and very reliable.