I don't think it's too much at all. I take 4 Asacol in the AM and I usually use a Canasa around the same time (sometimes I don't remember to use it until a bit later). The max dose of oral Asacol is 4800mg a day. 4 500mg tablets is only 2000mg, you could probably increase the dose but you should call your GI and see what s/he thinks before doing so.
Are you going to switch to Asacol or Lialda? Lialda is very easy and they say you can take all your pills at once in the morning - it's great for convenience. I am not sure if it is as effective if you take them at once but many do well using it this way. I tried Lialda but I did better on Asacol 400 so I switched back. I would like to try Lialda again but I don't want to risk being unstable for conveinence. I used to take my Asacol 3x a day, now I take it 2x a day and I don't notice a difference in my condition.
I have never taken sulfasalazine but I have read that it has higher incidence of side effects compared to the newer medications.
Sorry about your skin tag :( This DD is so unfair. I have been dealing with a fissure and that has been awful too!!