Wow. 100 attributes is something. I mean we've already gone above 50, but that's about double that.
I cannot provide you with a definite answer to you question, but would like support you postulating an answer ;)
I expect, that in such case everything comes into play:
- the kind of datatypes you use (textlines and XML blocks probably are on two opposite poles of processing cost),
- the kind and frequency of operations you will the objects for,
- the kind of caching, fetching etc. in relation to these giant objects... - server's ability to cope with those objects with a solid margin before timeouts...
BTW. is there no way to reduce the amount? For example, by joining several XML Blocks and/or text lines into one, formatted XML Block?