Hi Chris, i also like the 14x8 apc with my 100, i only use 15% powermaster but its the only affordable fuel i have access to but it seems to fly great!
i have had the same problem with my cowl cracking and have remidied it with small pieces of ca hinge cut to the appropriate size with 6min epoxy glues to the inside and that stops the crack in its tracks
other than that ive had no issues with this plane except i would like it to be a little lighter.