Is .exe size even an issue? I mean if you were really concerned about code size, code effeciency, binary size you wouldnt be using Darkbasic Pro.
Besides, I find it hard to believe that even a 100 mb exe file would be much challenge for modern computers. According to Steams hardware survey, 72% of all thier users have machines with 500-2gb RAM, Disk space is so abundant that its almost not worth even considering.
http://www.steampowered.com/status/survey.html
On the other hand if your making software for a PDA or phone or something then you probably wouldnt want to use DBPro.
Thats just my 2 cents, dont worry about .exe size.
-T